Electric timepiece

ABSTRACT

An electric watch is characterized by including a transmitting circuit  6  for generating a plurality of transmitted signals, transmitting electrodes  1  and  2  for outputting the output signals generated by the transmitting circuit  6 , a signal modulating member  3  composed of a rotor arranged adjacently to the transmitting electrodes  1  and  2  in a non-contact manner for modulating the transmitted signals, a receiving electrode  4  arranged adjacently to the signal modulating member  3  in a non-contact manner for receiving the transmitted signals modulated by the signal modulating member  3 , a receiving circuit  7  for amplifying received signals received by the receiving electrode  4 , and a detecting circuit  8  for detecting mechanical position information of the signal modulating member  3  based on the received signal amplified by the receiving circuit  7.

TECHNICAL FIELD

The present invention relates to an electric watch for mechanicallydisplaying time and calendar information using a quartz oscillatingcircuit as a reference signal source, which is provided with a positiondetecting system which detects a rotating angle or a rotating positionof a wheel train or the like by detecting an electric field, therebymechanical mis-operations are preventing from being occurred so as todisplay correct time information.

BACKGROUND ART

Conventionally, power consumption decreasing techniques for electricwatches are established, and small primary batteries are used as powersources of the electric watches. The primary batteries are, however,disposable, and replacement of batteries is troublesome, and it isestimated that terrestrial environmental pollution due to the disposalof the primary batteries becomes more serious problem in the future. Inview of such problems, power generating type electric watches, which usesecondary batteries charged with power generating energy instead of theprimary batteries, are put into practice. The power generating energy isobtained from energy sources such as solar power generation using solarbattery, thermoelectric power generation using a temperature differencebetween an atmosphere and a wrist, and mechanical power generation usinga revolution cone.

The power generating type electric watches, therefore, are eco-friendly,but the energy to be built up is not enough, and thus there arises apotential problem that the lack of the charged energy with which thesecondary batteries are charged deteriorates reliability of timeholding. Particularly in mechanical analog wrist watches, in order toreduce the consumption of the energy as much as possible, a wheel trainmechanism is driven by a minimum driving torque. For this reason, when ashape of hands is large, there is a fear that time indication by thehands is shifted due to shock, disturbance, and the like, and in orderto prevent this, the shape and size of the hands have a certainlimitation.

Further, in a calendar display mechanism of mechanical electric watchesfor displaying time using mechanical hands, date of a date displaysection should be corrected manually at the end of the monthapproximately every two months. For this reason, it is very troublesomeand difficult to use the mechanical electric watches. When a complicatedmechanism is adopted, a month-end automatic correcting function can beadded, but since such a function has a complicated mechanism, theassembly cost becomes high, and the reliability of a stable operationfor a long time is deteriorated. Since the power consumption increases,it is difficult to operate in an uninterruptible manner with thecharging energy. When only a date section adopts electro-optical liquidcrystal display in order to solve this problem, a time display surfaceprovides improper design.

In order to eliminate the above disadvantage, a function for detecting amechanical angle and a rotating position of hands display and calendardisplay is necessary. Conventionally suggested techniques are asfollows. (1) Japanese Patent Application Laid-Open No. 57-67877discloses a technique that a mechanical switch is provided to a portionof a rotational wheel train. (2) Japanese Patent Application Laid-OpenNo. 8-179058 discloses a technique that a light emitting element and alight receiving element are arranged so as to sandwich a rotationalwheel train having a hole and the light receiving element detectspresence/non-presence of the hole at the time of rotation. (3) JapanesePatent Application National Publication No. 2001-524206 or (4) U.S. Pat.No. 6,307,814 discloses capacity detection in which electronic detectingmeans detects a change or the like in electric properties includingcapacity change between electrodes utilizing a rotating member.

Publicly known references relating to the present invention include: (5)Japanese Patent Application Laid-Open No. 54-91278 which discloses aposition detecting system which is provided with a mechanically contactswitch on a part of a rotational wheel train; (6) Japanese PatentApplication Laid-Open No. 2000-35489 which discloses a system where alight emitting element and a light receiving element are arranged so asto sandwich a rotational wheel train having a hole and a light receivingoptical switch detects presence/non-presence of the hole at the time ofrotation; and (7) Japanese Patent Application Laid-Open No. 54-92360which discloses a position detecting mechanism adopting capacitydetection for detecting a change in a capacity between hands, a wheeltrain or the like and a position detecting member due to a rotatingmovement.

The position detecting mechanisms which have been suggested, however,have a lot of disadvantages. The position detection (1) which utilizesthe mechanical contact switch mechanism has a constitution where aposition is detected by contacting with the rotating movement membersuch as the wheel train, and thus requires many driving energy. Thisdisadvantage becomes a serious problem particularly for the powergenerating type electric watches having insufficient power generatingenergy, and the position detection might cause a shift of the position.Further, the contact switch mechanism causes abrasion of the contactmember, and thus reliability is low.

In the constitution (2) utilizing an optical sensor, since it isnecessary to arrange the light emitting element and the light receivingelement on upper and lower surfaces of a rotating member, a thickness ofthe watch increases. For this reason, this constitution cannot beadopted to thin wrist watches. Considerable electric power consumptionis required to operate optical elements such as the light emittingelement and the light receiving element, and thus the detection iscarried out only about once a day. Since driving voltage having athreshold value higher than a certain value is necessary for lightemission, it is difficult to apply this constitution to power generatingelectric watches having large fluctuation in a power supply voltage.

In the constitution (3) or (4) where a change in the capacity betweenthe electrodes is directly detected by the rotating member, since achange in the capacity which is detected by a very small positiondetecting part adaptable to a size of wrist watches is very small,detecting accuracy is low. Further, the detection is easily influencedby external environment such as changes in position, temperature and thelike due to carrying postures, and thus the reliability of the positiondetection is very low.

It is an object of the present invention to provide an electric watchhaving a position detecting system with high reliability for beingcapable of securely detecting a time difference between mechanicalholding time and electric holding time. The position detecting system ofthe present invention solves the above problems, does not require a lotof energy, avoids a problem caused by a defective contact or the likedue to aged deterioration of a contact type detecting mechanism so as toprevent deterioration of reliability, realizes a constitution thinnerthan an optical sensor system, does not require a high voltage fordriving a light emitting element, and is not influenced by externalenvironment such as temperature as compared with a system for detectinga change in an electrostatic capacity and in an absolute quantity of amagnetic force.

DISCLOSURE OF THE INVENTION

In order to achieve the above object of the present invention, thepresent invention basically adopts following technical constitutions.

That is to say, a first aspect of a basic constitution of an electricwatch having a detecting mechanism for detecting position information ofa rotating member to be measured according to the present invention,characterized by including:

a transmitting circuit for generating a plurality of transmittedsignals;

a transmitting electrode for outputting output signals generated by thetransmitting circuit;

a signal modulating member comprising a rotating member and arrangedadjacently to the transmitting electrode in a non-contact manner formodulating the transmitted signals;

a receiving electrode arranged adjacently to the signal modulatingmember in a non-contact manner for receiving the transmitted signalsmodulated by the signal modulating member;

a receiving circuit for inputting the received signal received by thereceiving electrode; and

a detecting circuit for detecting mechanical position information of thesignal modulating member based on the received signal input into thereceiving circuit.

Further, a second aspect of the basic constitution of an electric watchhaving a detecting mechanism for detecting position information of arotating member to be measured according to the present invention,characterized by including:

a transmitting circuit for generating a plurality of transmittedsignals;

signal modulating means having a transmitting electrode, to which anoutput signal of the transmitting circuit is applied, a receivingelectrode for receiving signals from the transmitting electrode, and arotor arranged between the transmitting electrode and the receivingelectrode for modulating the transmitted signals output from thetransmitting electrode;

a receiving circuit for inputting modulated signals received by thereceiving electrodes;

a reference signal generating circuit for generating a reference signalfor detecting the position information of the rotor based on thetransmitted signals output from the transmitting circuit; and

a detecting circuit for comparing the output signals from the receivingcircuit with the reference signal from the reference signal generatingcircuit so as to detect mechanical position information of the rotor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating a schematic signal modulatingconstitution according to a first example of the present invention.

FIG. 2 is a sectional view of FIG. 1.

FIGS. 3( a), 3(b), 3(c) and 3(d) are waveform charts for explaining aprinciple of modulation of a signal according to the present invention.

FIGS. 4( a) and 4(b) are explanatory diagrams illustrating amplitude andphase properties of a detected signal according to the presentinvention.

FIGS. 5( a), 5(b), 5(c), 5(d) and 5(e) are diagrams illustratingvariations of a signal transmission path.

FIG. 6 is a perspective view of the first example where the presentinvention is applied to a watch.

FIG. 7 is a perspective view illustrating another example of a detectingwheel.

FIG. 8 is a block diagram of an entire watch system according to thefirst example.

FIG. 9 is a circuit diagram of a transmitting circuit according to thefirst example.

FIG. 10 is a circuit diagram of an equivalent circuit of a modulatingmechanism and a receiving circuit according to the first example.

FIG. 11 is a waveform chart illustrating signal waveforms of respectiveportions according to the first example.

FIG. 12 is a circuit diagram where a phase of a received signal isdetected according to the first example.

FIG. 13 is a waveform chart of a detected signal which is an output ofthe detected result in FIG. 12.

FIG. 14 is a diagram illustrating an output of another detecting circuitaccording to the first example.

FIG. 15 is a circuit diagram of the detecting circuit for obtaining theoutput of FIG. 14.

FIGS. 16( a) and 16(b) are a circuit diagram and a block diagram of anoise control circuit according to the first example.

FIGS. 17( a) and 17(b) are a circuit diagram and a block diagram ofanother noise control circuit according to the first example.

FIGS. 18( a) and 18(b) are diagrams illustrating each singletransmission path detected output and differential output properties ofa plurality of transmission paths according to the first example.

FIGS. 19( a), 19(b) and 19(c) are diagrams for explaining anotherexample of the first example.

FIG. 20 is a diagram illustrating a relationship between a drivingtiming of a motor and a wheel track position detecting timing in thewatch according to the first example.

FIG. 21 is a plan view illustrating a day plate where the first exampleis applied to a calendar display watch.

FIG. 22 is a block diagram illustrating a constitution of a positiondetecting system of an electric watch according to a second example ofthe present invention.

FIGS. 23( a), 23(b) and 23(c) are sectional views illustrating apositional relationship between a transmitting electrode, a receivingelectrode and a hole portion of a rotor.

FIG. 24 is a functional block diagram of the second example.

FIG. 25 is a block diagram illustrating a constitution according to athird example of the present invention.

FIG. 26 is a block diagram illustrating a constitution according to afourth example of the present invention.

FIG. 27 is a diagram explaining a reason that a reference signal shouldbe finely adjusted according to the third and fourth example of thepresent invention.

FIG. 28 is a diagram explaining a fifth example of the presentinvention.

FIG. 29 is a diagram explaining the fifth example of the presentinvention.

FIG. 30 is a diagram explaining the fifth example of the presentinvention.

FIG. 31 is a flowchart illustrating an operation according to the fifthexample of the present invention.

FIG. 32 is a block diagram illustrating a constitution according to asixth example of the present invention.

FIG. 33 is a waveform chart for explaining fine adjustment of the phaseof the position detecting system according to the sixth example of thepresent invention.

FIG. 34 is a block diagram illustrating another constitution accordingto, the sixth example of the present invention.

FIG. 35 is a sectional view of a wheel train mechanism including signalmodulating means in the position detecting system of the electric watchaccording to a seventh example of the present invention.

FIG. 36( a) is a plan view of the receiving electrode according to theseventh example; FIG. 36( b) is a plan view of the detecting wheelaccording to the seventh example, FIG. 36( c) is a plan view of thetransmitting electrode according to the seventh example; and FIG. 36( d)is a plan view of the transmitting electrode according to an eighthexample.

FIG. 37 is an explanatory diagram of a phase change of a received signalaccording to the seventh example.

FIG. 38 is an explanatory diagram of a phase change of a received signalaccording to the eighth example.

FIG. 39 is a diagram explaining a ninth example: FIG. 39( a) is a planview of the receiving electrode; FIG. 39( b) is a plan view of thedetecting wheel; and FIG. 39( c) is a plan view of the transmittingelectrode.

FIG. 40 is an explanatory diagram of a phase change of a received signalaccording to the ninth example.

FIG. 41 is a diagram explaining a tenth example: FIG. 41 (a) is a planview of the transmitting electrode; FIG. 41( b) is an explanatorydiagram when the transmitting electrode of the seventh example is used;and FIG. 41( c) is an explanatory diagram when the transmittingelectrode of the tenth example is used.

FIG. 42 is an explanatory diagram for comparing phase changes of thereceived signals when the transmitting electrode of the seventh exampleand the transmitting electrode of the tenth example are used.

FIG. 43 is a plan view of the transmitting electrode according to aneleventh example.

FIG. 44 is an explanatory diagram illustrating a phase change of areceived signal according to the eleventh example.

FIG. 45 is a diagram explaining a twelfth example: FIG. 45 (a) is a planview of the receiving electrode; FIG. 45( b) is a plan view of thedetecting wheel; and FIG. 45( c) is a plan view of the transmittingelectrode.

FIG. 46 is an explanatory diagram illustrating a phase change of areceived signal according to the twelfth example.

FIG. 47 is a plan view of the transmitting electrode according to athirteenth example.

FIG. 48 is an explanatory diagram illustrating a phase change of areceiving signal according to the thirteenth example.

FIG. 49 is a diagram illustrating a sectional constitution of theposition detecting system in the electric watch according to afourteenth example of the present invention.

FIG. 50 is a diagram illustrating another sectional constitution of theposition detecting system in the electric watch according to thefourteenth example of the present invention.

FIG. 51 is a diagram illustrating another sectional constitution of theposition detecting system in the electric watch according to thefourteenth example of the present invention.

FIG. 52 is a partial sectional view of a fifteenth example of thepresent invention.

FIG. 53( a) is a plan view of the detecting wheel according to thefifteenth example; and FIG. 53( b) is a plan view of the transmittingelectrode and the receiving electrode according to the fifteenthexample.

FIG. 54 is a block diagram illustrating an electric constitutionaccording to the fifteenth example.

FIG. 55 is a plan view illustrating a change in a position relationshipbetween a relay electrode and the plural transmitting electrodes whenthe relay electrode arranged on the detecting wheel of the fifteenthexample rotates once about a shaft: FIGS. 55(A) to 55(I) are statediagrams at steps of every 400.

FIG. 56 is a graph illustrating a phase relationship between thetransmitted signal and the received signal according to the fifteenthexample: FIG. 56( a) illustrates a positional relationship when thereceived signal is +15°; FIG. 56( b) illustrates a phase relationshipwhen the received signal is +45°; and FIG. 56( c) illustrates a phaserelationship when the received signal is −45°.

FIG. 57( a) is a graph illustrating a phase change in the receivedsignal every one second with respect to a rotating amount of thedetecting wheel according to the fifteenth example; and FIG. 57( b)illustrates a waveform of a position signal Pd corresponding to thereceived signal.

FIG. 58 is a plan view illustrating a constitution of the transmittingelectrode and the receiving electrode according to a sixteenth example.

FIG. 59 is a partial sectional view of the position detecting systemaccording to a seventeenth example.

FIG. 60 is a partial sectional view of the position detecting systemaccording to an eighteenth example.

FIG. 61 is a plan view illustrating a position relationship between thetransmitting electrode, the receiving electrode and the relay electrodeaccording to a nineteenth example: FIG. 61( a) is a plan view of thetransmitting electrode and the receiving electrode; FIG. 61( b) is aplan view of the relay electrode arranged on the detecting wheel; andFIGS. 61( c) to 61(f) are plan views illustrating a positionrelationship between the transmitting electrode, the receiving electrodeand the transmitting electrode.

BEST NODE FOR CARRYING OUT THE INVENTION

The examples of an electric watch according to the present invention aredetailed below with reference to the drawings.

FIRST EXAMPLE

FIGS. 1 to 21 are diagrams for explaining a first example of the presentinvention.

The first example of the present invention realizes a basic constitutionof the electric watch of the present invention. Concretely, the electricwatch which has a mechanism for detecting an angle rotating position ofa rotating member to be measured includes a transmitting circuit, atransmitting electrode, a signal modulating member, a receivingelectrode, a receiving circuit, and a detecting circuit. Thetransmitting circuit generates a plurality of transmitted signals. Thetransmitting electrodes outputs the output signals generated by thetransmitting circuit. The signal modulating member is arrangedapproximately to the transmitting electrode in a non-contact manner andis composed of a rotor for modulating the transmitted signals. Thereceiving electrode is arranged approximately to the signal modulatingmember in a non-contact manner and receives the transmitted signalsmodulated by the signal modulating member. The received signal receivedby the receiving electrode is input to the receiving circuit. Thedetecting circuit detects mechanical position information of the signalmodulating member based on the received signal received by the receivingcircuit.

With reference to FIGS. 1 to 5, a basic operation of the presentinvention is explained below.

FIG. 1 is a plan view illustrating a schematic signal modulating sectionof the electric watch according to the present invention, and FIG. 2 isa sectional view of FIG. 1.

In FIGS. 1 and 2, reference numerals 1 and 2 designate the transmittingelectrodes, and the transmitting electrodes 1 and 2 are arranged so asto be opposed to the receiving electrode 4 across the rotor 3 as thesignal modulating member. The transmitting electrodes 1 and 2 adjoin therotor 3 in a non-contact manner, and the rotate 3 adjoins the receivingelectrode 4 in a non-contact manner. The transmitted signals from thetransmitting electrodes 1 and 2 reach the receiving electrode 4 via ahole 5 with a line of electric force extending from both thetransmitting electrodes 1 and 2. The rotor 3 is a gear-like object of awrist watch wheel train, for example, and is made of a metal or plasticmaterial coated with metal so as to have electrical conductivity. Therotor 3 is arranged so that its axis, not shown, or another portion iselectrically grounded.

The numeral 6 designates the transmitting circuit for outputting aplurality of transmitted signals, and it forms two kinds of transmittedsignals φA and φB of a sine wave with different phases and samefrequency, for example. The transmitting electrode 1 outputs thetransmitted signal φA, and the transmitting electrode 2 outputs thetransmitted signal φB. The transmitted signals φA and φB are received asa received signal φC by the receiving electrode 4 via the rotor 3 formodulating the transmitted signals φA and φB.

Although amplitude of the received signal φC is greatly lowered ascompared with those of the transmitted signals φA and φB, the receivedsignal φC is induced from a synthesized electric field of thetransmitted signals φA and φB. For this reason, if when the frequenciesof the transmitted signals φA and φB are equal with each other, thefrequency of the received signal φC is also equal thereto, and if whenthere is a phase difference between the transmitted signals φA and φB,the received signal φC takes a middle phase between these phases. Thehole 5 moves according to rotation of the rotor 3, a spatial relativeposition relationship between the transmitting electrodes 1 and 2 andthe receiving electrode 4 changes. Further, amplitude and phase of an ACsignal from the receiving electrode 4 to be induced change due tooverlapping of the electric field in the vicinity of the receivingelectrode 4. That is to say, when the position of the hole 5 of therotor 3 changes and thus the spacial relationship between thetransmitting electrodes 1 and 2 and the receiving electrode 4 changesaccording to a rotating angle θ of the hole 5 of the rotor 3, the phaseand the amplitude of the received signal φC change as functions of therotating angle θ.

When the received signal φC is amplified by the receiving circuit 7, thesine wave signal with large amplitude is saturated so as to have atrapezoid shape, and when it is further amplified, the sine wave signalbecomes a detected signal Pc of a rectangular waveform. Since the phaseinformation is maintained even in this case, the phase information canbe extracted easily by phase detection. This method is equivalent to amechanism of high-quality FM broadcasting. A different point is that abroadcasting station modulates frequency or phase of a signal and thentransmits the signal, but in the present invention, the phase of thereceived signal is modulated by mechanical change of the rotor providedon a transmission path between the transmitting electrodes and thereceiving electrode. The present invention is similar to the FMbroadcasting in that disturbance due to noise in a watch mechanism orcircuit noise is eliminated efficiently by phase detecting means.

The detected signal Pc is input into the detecting circuit 8, and themechanical position information of the rotor 3 is obtained from thereceived signal φC. The detecting circuit 8 maybe a phase detectingcircuit for detecting phase information, or an amplitude detectingcircuit for detecting amplitude information. Relative intensityinformation of the received signal is detected by the amplitudedetecting circuit so that the mechanical position information is roughlydetermined, and the phase information of the received signal is detectedby the phase detecting circuit so that the mechanical positioninformation may be determined.

FIG. 3 is a waveform chart illustrating modulation processes of thereceived signal φC according to the embodiment shown in FIGS. 1 and 2.When the position of the hole 5 is distant from the transmittingelectrodes 1 and 2, the line of electric force obtained by thetransmitted signal φA to be applied to the transmitting electrode 1 andthe line of electric force obtained by the transmitted signal φB to beapplied to the transmitting electrode 2 are shielded by the electricallyconductive rotor 3. In this state, a voltage induced by the receivingelectrode 4 becomes a signal with very small amplitude as shown in FIG.3( a). In this state, a meaningless noise component mostly occupiesresidual phase information.

When the rotor 3 is rotated and the hole 5 is positioned between thetransmitting electrode 1 and the receiving electrode 4 as shown in FIG.2, the signal from the transmitting electrode 1 is transmitted to thereceiving electrode 4, but the signal from the transmitting electrode 2is shielded by the rotor 3 so as not to be transmitted. That is to say,the amplitude of the received signal φC is small as shown in FIG. 3( b),but its phase is the approximately same as that of the transmittedsignal φA.

When the rotor 3 further rotates and the hole 5 moves to a direction ofan arrow in FIG. 2 so as to be positioned in a middle position betweenthe transmitting electrode 1 and the transmitting electrode 2 as shownin FIG. 1, a signal obtained by synthesizing the transmitted signals φAand φB is transmitted to the receiving electrode 4. For this reason, asshown in FIG. 3( c), the received signal φC becomes a signal having anintermediate phase between the phases of the transmitted signals φA andφB.

When the rotor 3 further rotates and the hole 5 is positioned betweenthe transmitting electrode 2 and the receiving electrode 4, only thetransmitted signal φB is transmitted to the receiving electrode 4. Forthis reason, the received signal φC becomes a signal with theapproximately same phase as that of the transmitted signal φB as shownin FIG. 3( d).

That is to say, when the hole 5 of the rotor 3 is distant from thevicinities of the transmitting electrodes 1 and 2, the amplitude of thereceived signal φC is almost zero. When the rotor 3 rotates continuouslyand passes through the transmitting electrodes 1 and 2, the receivedsignal φC transmit a signal with an amplitude and the phase of thereceived signal φC gradually changes from the phase of the transmittedsignal φA to the phase of the transmitted signal φB. The phase change orthe amplitude change of the received signal φC, or both of them is orare detected, so that a reference position of the rotor 3 can bedetected.

In the constitution of FIGS. 1 and 2, proximity of the hole 5 isdetected from the amplitude of the received signal φC, and when theamplitude is not less than a certain value, a determination is made thatthe phase detected information of the received signal φC is proper. As aresult, the position of the rotor 3 can be detected easily. When theamplitude of the received signal φC is not more than the certain value,a publicly known squelch circuit is operated so as to stop the operationof the hole position detecting circuit. When the electrically conductiverotor 3 is used, since the effect for shielding the transmitted signalsφA and φB with respect to the received signal φC is great, the squelchoperation is easily utilized. A concrete configuration of the squelchcircuit is detailed later.

The phase of the received signal φC takes a value between the phases ofthe transmitted signals φA and φB as mentioned above, and the amplitudealso changes as the function of the mechanical position of the rotor 3.This can be easily derived from a synthesized formula of a trigonometricfunction representing the electric field. Hereinafter, particularly whenthe AC signals φA and φB are expressed as a time periodic function of anangular velocity ω in which time t is a variable, they are representedby φA(ωt) or φB(ωt). They are also represented by φA and φB inabbreviated form. The reference position detection using two transmittedsignals with different phases is explained, but the position detectionusing signals with different frequencies is also possible.

The relationship between the amplitude and the phase of the receivedsignal φC is further explained below with reference to FIG. 4. FIGS. 4(a) and 4(b) illustrate the relationship between the phase and theamplitude of the received signal φC when the transmitted signals φA andφB have the same frequency but different phases. FIG. 4( a) is a diagramin which the received signal φC is vector-displayed with Cos(ωt) isplotted along the x axis and Sin(ωt) is plotted along the y axis.

In FIG. 4( a), when the hole 5 is positioned just below the transmittingelectrode 1 for transmitting the transmitted signal φA, the receivedsignal φC is represented by Ps(a). When the hole 5 is positioned justbelow the transmitting electrode 2 for transmitting the transmittedsignal φB, the received signal φC is represented by Ps(b). When the hole5 is positioned in a middle position between the transmitting electrodes1 and 2, the received signal φC is represented by Ps(m) (s=1, 2, 3).

A path 31 which passes from the P1 (a) to P1 (b) via P1 (m) represents avector trajectory when a phase difference between the transmittedsignals φA and φB is π/2. Similarly, a path 32 which passes from P2 (a)to P2 (b) via P2 (m) represents a vector trajectory when the phasedifference between the transmitted signals φA and φB is 3π/4 A path 33which passes from P3 (a) to P3 (b) via P3 (m) represents a vectortrajectory when the phase difference between the transmitted signals φAand φB approaches π. The respective points on the paths are representedby Ps (x).

Amplitude of detecting voltage at the points Ps (x) on the paths isrepresented by a length of the vector of point 0→point Ps (x). Theamplitude of the received signal φC is expressed by a relative value.The phase of the detecting voltage at the point Ps (x) on the paths isrepresented by a component of a projected length on the x axis. Forexample, on the path 33 where the phase difference between thetransmitted signals φA and φB is π, the phase advances by π/2 and theamplitude moves from P3 (a) as a starting point at which the amplitudeis equal with a radius r of a circle passing through at P3(m) at whichthe phase becomes zero and the amplitude is small to P3(b) at which thephase delays by π/2 and the amplitude is equal with the radius r of thecircle.

FIG. 4( b) is a diagram illustrating the relationships between the phaseand the amplitude, respectively, as the function of the rotating angleof the rotor 3. In FIG. 4( b), a moving distance of the hole 5 of therotor 3 is plotted along a lateral axis, and the amplitude and the phaseare plotted along a vertical axis. When the phase difference between thetransmitted signals φA and φB is π/2, 3π/4 and about π, the path of theamplitude is expressed by line 34, 35 and 36, respectively, and the pathof the phase is expressed by lines 37, 38 and 39, respectively.

As shown in FIG. 4( b), as the phase difference between the transmittedsignals φA and φB exceeds π/2 so as to increase up to π, an amplitudefluctuation is large and a difference in the modulated phase is alsolarge.

When the phase difference between the transmitted signals φA and φBapproaches to π, the amplitude of the received signal φC showsdouble-humped characteristics, and the amplitude in the middle betweenthe humps is lowered, thereby disturbing the detection of the phaseinformation. For this reason, it is preferable that the phase differenceis set to be smaller than π to a certain extent. Practically, it isnecessary to extract and use only the received signal phase informationin the position of the rotating angle for providing large receivingamplitude. The amplitude, however, can be uniform by saturating andamplification as long as the amplitude does not become extremely small.

When the change in the amplitude is used for not the phase detection butfor the position detection, the phase difference between the transmittedsignals φA and φB is set to be close to π, so that steepness of theamplitude function of the received signal φC in the vicinity of thecenter of the hole can be utilized. That is to say, as the rotation ofthe rotor 3 proceeds, after the position with large amplitude isdetected, abrupt decrease or increase in the amplitude is detected,thereby detecting the reference position.

One of requirements which a plurality of transmitted signals satisfiesis that the transmitted signals include a plurality of AC vector signalcomponents in an orthogonal relationship, and the amplitude of thevector sum of the received signal is not 0 all the time. When Sin(ωt) isapplied to one electrode, the other electrodes should include a Cos(ωt)component which is orthogonal to the signal or a high-frequencycomponent. When the two transmitting electrodes are, therefore, used,and a phase difference α is set according to the following equations:φA=Sin(ωt−α/2)φB=Cos(ωt+α/2); (ω and α are constants, and t is time),it is necessary that α>π, when phase difference α is to be set.

It is not necessary that both the signals do not always establish theorthogonal relationship, but they should include orthogonal vectorcomponents. When the orthogonal components composed of differentfrequencies are, for example, as follows:φA=Sin(ωt+β)φB=Sin(n×ωt+γ); (n=2, 3, 4 . . . ; β and γ are constants),synchronous detection is made by using a common signal which is thebasis for creating the transmitted signals φA and φB as a referencephase, and a differential amplifying circuit is used for extracting aposition detecting signal from a difference between the synchronousdetecting output signals.

Constitutions of the various transmission paths for thetransmitted/received signals are explained below with reference to FIG.5. FIG. 5 is an explanatory diagram of the transmission paths for theposition information detected signals, and FIGS. 5(a) to 5(e) illustratefive kinds of embodiments.

FIG. 5( a) is an explanatory diagram illustrating the constitutioncomposed of a plurality of transmitting electrodes 51 and 52 and asingle receiving electrode 55. Transmitted signals 53 and 54 withdifferent phases or frequencies from the transmitting electrodes 51 and52 pass through the hole of a rotor 500 and are synthesized so as to betransmitted to the receiving electrode 55. That is to say, the signalswith the same frequency and different phases or the signals withdifferent frequencies are transmitted from the electrodes 51 and 52, andare received by the receiving electrode 55 on the receiving electrodeside. A position information of the rotor 500 is extracted as thefunction of the mechanical position of the rotor 500 from a differencein the transmitting properties between the transmission paths.Particularly the phase demodulation transmitting/receiving systemsuppresses an influence of disturbing electric field noise so as to becapable of measuring an accurate position of a wheel train. Thiscorresponds to an FM (frequency modulation=equivalent phase modulation)broadcasting system which has good sound quality and is resistant to anoise radio.

The constitution of FIG. 5( a) is a first candidate of the positiondetecting mechanism of the present invention. The constitution, in whichsignals with different phases are transmitted simultaneously and achange in the phase of the received signal is detected, has highdetecting sensitivity and reliability as mentioned below. Thetransmitting electrodes 51 and 52 transmit sine wave signals havingfrequency of several kHz and a phase difference of several dozen° tohundred and several dozen°, and the receiving electrode 55 receivessignals whose phase and amplitude are modulated by the rotor, anddetects and analyzes the signals.

The transmission and reception are carried out with the timing beingshifted, and the received information is stored in a storage circuit,and a plurality of data received later are compared. Such a method canbe used but the following method is superior to this. That is to say,signal differential operations of the different transmission paths areprosecuted simultaneously in the transmission path space, so that thesignal difference is detected from a circuit noise and an operationerror. The simultaneous transmission can generate an interferenceelectric field due to overlapping of the transmission paths and thecommon receiving electrode. As a result of the overlapped interferenceof the transmitted signals 53 and 54 on the receiving electrode 55, asignal whose phase and the amplitude are modulated can be obtained.Since the differentiation is carried out by the interference of anelectromagnetic wave according to a principle of the electromagneticoverlapping, no noise is generated and S/N is not deteriorated, and thisis a superior method. As mentioned above, it is a characteristic of thepresent invention that the rotor 500 is used as the phase modulatingmeans which is sensitive to the electromagnetic wave.

A system for transmitting a plurality of transmitted signals atdifferent timings is considered. In this case, the receiving electrode55 receives a single sine wave signal, but since the same internalsystem of the watch is used, an accurate phase of the received signal byusing a signal from a transmitting source as a reference can bemeasured. The phases of the signals received from the differenttransmitting electrodes at different timings on a time base can bemeasured accurately. Since a circuit process for taking a difference ofthe phase and amplitude of the minute signals is, however, executed viathe receiving circuit, this system is inferior to a simultaneoustransmitting simultaneous receiving constitution, in which adifferential process can be executed directly by utilizing theoverlapping principle on the transmission paths, in view of S/N.

FIG. 5( b) is an explanatory diagram of a constitution composed of theplural transmitting electrodes 56 and 57 and the plural receivingelectrodes 60 and 61. The transmitting electrodes 56 and 57 transmit thesignals 58 and 59 with different phases or frequencies, and the signalspasses through the hole of the rotor 500 so as to be transmitted to thereceiving electrodes 60 and 61, respectively.

That is to say, this is a system for comparing a difference in thetransmission characteristics between the transmission paths using thereceiving electrodes 60 and 61 so as to measure and analyze thedifference. In the measurement on the transmission paths of the singletransmitting electrode and the single receiving electrode, since anerror due to mechanical jolting of the wheel train is directly detected,a detecting error is large, and thus the reliability of the measuredresult is fairly deteriorated. The detection can be made by themodulation of amplitude or the modulation of phase, but the differencebetween the received signals is created and they are compared at aprocess in the circuit after the signals is received on the receivingelectrodes 60 and 61. For this reason, the detection is easilyinfluenced by an internal noise of the circuit, and as compared with theconstitution in FIG. 5( a), the sensitivity of the position detectiontends to be deteriorated.

FIG. 5( c) is an explanatory diagram of a constitution composed of thesingle transmitting electrode 62 and the plural receiving electrodes 65and 66. The transmitting electrode 62 transmits a plurality of signals63 and 64, and the signals pass through the hole of the rotor 500 so asto be transmitted to the receiving electrodes 65 and 66.

That is to say, the constitution is such that the single transmittingelectrode 62 and the plural receiving electrodes 65 and 66 are provided,and signals induced in the receiving electrodes 65 and 66 are comparedreciprocally. The reception timing and the comparison timing are notnecessarily simultaneous on the receiving electrodes 65 and 66. Sincethe signals have the equal frequency and approximately equal phase, ahomodyne detecting method, in which simultaneous detection is executedbased on the transmitted signals and filtering is executed in order toeliminate a noise, is adopted. This method has less advantages because anumber of electrodes is not decreased and further the detecting accuracyis deteriorated.

The complication of the circuit for creating the plural transmittedsignals 63 and 64 is, however, decreased. When the receiving electrodes65 and 66 detect the positions of the plural wheel members, timedivision is carried out so that the transmitting electrode 62 and thereceiving electrodes 65 and 66 are successively classified into groups,and time division can be switched. In this case, the constitutioncomposed of the single transmitting electrode 62 and a plurality ofreceiving electrodes 65 and 66 can be used to detect positioninformation of a day plate where error tolerance is large.

FIG. 5( d) is an explanatory diagram of a constitution composed of thesingle transmitting electrode 69 and the single receiving electrode 70.The single transmitting electrode 69 transmits signals 68 and 67 withdifferent frequencies in a synchronous relationship and the signals passthrough the hole of the rotor 500 so as to be transmitted to thereceiving electrode 70.

That is to say, a pair of the transmitting and receiving electrodes arearranged in the vicinity of the rotor 500, radio waves with differentfrequencies are transmitted from the transmitting electrode 69 and arereceived by the receiving electrode 70 simultaneously or at differenttimes which are close to each other temporally. Transmittingcharacteristic data corresponding to the frequencies are comparedreciprocally in the same position of the rotor, and a change in adifference between the transmitting characteristics is taken as thefunction of the rotating position of the wheel train, so that theposition of the rotor 500 can be estimated. This system has an advantagesuch that a number of the electrodes is two.

FIG. 5( e) is an explanatory diagram of a constitution in which oneelectrode is used as both the transmitting electrode and the receivingelectrode. The transmitting/receiving electrode 71 transmits signals 72and 73 with different frequencies, and the signals pass through thevicinity of the rotor 500 so as to be received by thetransmitting/receiving electrode 71.

That is to say, only one electrode is prepared for both the transmittingelectrode and the receiving electrode, and the electrode is driven via ahigh-output impedance element by a constant voltage driving circuitusing a plurality of AC sources with different frequencies. An electrodevoltage of the transmitting/receiving electrode 71 adjacent to the rotorand its phase are compared with a voltage of the constant voltagedriving circuit and its phase. A change is detected by an I/O terminalof a driving integrated circuit and the constant voltage driving circuitin the integrated circuit. In another manner, the measurement is carriedout by using different frequencies simultaneously or intermittently at aplurality of times which are close to each other temporally, so that themechanical position information of the rotor 500 is obtained fromfrequency dependency of electromagnetic load characteristics of thetransmitting/receiving electrode.

Although the detecting sensitivity is low, only one electrode is usedfor detection, so that the system can be miniaturized. Thehigh-impedance element uses high resistor formed in the watch integratedcircuit, so that influences of humidity and electromagnetic fieldoutside the integrated circuit are suppressed. The deterioration in thedetecting sensitivity and the influence of the jolting of the wheeltrain cannot be avoided, but this system can be sufficiently applied toclocks having enough volume.

The above-mentioned wheel train position detecting constitutions aregenerally explained. The electrodes arranged in the vicinity of thewheel train detect a change in a difference of the differentelectromagnetic components detected via the transmission paths as thefunction of the mechanical rotating position of the wheel train so as toobtain the position information of the wheel train.

That is to say, plural kinds of the AC signals are transmitted throughthe transmission paths which are spatially or temporally different, andthe electric field between the transmitting electrode and the receivingelectrode is modulated at least by a partially common member. As aresult, the difference of the transmission characteristics is generatedin the transmission space and is detected, so that the position of thewheel train is detected. In the actual watch mechanism, simplificationof the mechanism, reduction of volume, reduction of thickness, reductionin the cost of assembly and adjustment, reduction in the cost ofmembers, reduction in the cost of the driving/detecting integratedcircuit, and the like are demanded. The optimization is achieved underthese conditions. For this reason, a complicated constitution is notallowed, and the deterioration of the measuring accuracy and thereliability is not allowed.

The example in which the present invention is applied to a hand positiondetecting mechanism for a second hand of the wrist watch is detailedbelow. FIG. 6 is a perspective view of the wheel train portion havingthe second hand position detecting mechanism. In FIG. 6, the numeral 46designates a fifth wheel for decelerating and transmitting rotation of arotor in an electromechanical converting mechanism. The fifth wheel 46transmits the rotation of a same reducing ratio to a fourth wheel 47 anda detecting wheel 43 as a signal modulating member. A second hand 48 isfixed to the fourth wheel 47, and displays second information. Thefourth wheel 47 and the detecting wheel 43 move the second hand in asynchronous stepwise manner of 60 steps per rotation, namely, 6° perstep.

That is to say, in the present invention, the fourth wheel 47corresponds to one example of the rotating member to be measured in thisapplication.

On the other hand, the detecting wheel 43 may be another example of therotating member to be measured in this application.

The detecting wheel 43 is made of a metal member having electricalconductivity, and its bearing portion, not shown, is grounded. A gearportion of the detecting wheel 43 has a hole 45. Conductivity orpermittivity of the hole portion of the detecting wheel 43 is differentfrom that of another portion thereof separated from the hole 45 in thedirection due to the hole 45. The hole 45 of the detecting wheel 43 isnot limited to an actual hole form, and may be a notched form or aconvexo-concave form in a sectional direction of the gear as long as adistance between an upper/lower surface of the gear and the electrodeschanges due to the rotation. The transmitting electrodes 41 and 42 areprovided on a top side of the gear of the detecting wheel 43, and thereceiving electrode 44 is provided on a bottom side. They are opposed toeach other so as to be adjacent in a non-contact manner.

Every time when the detecting wheel 43 rotates by one step, thetransmitting electrodes 41 and 42 transmit sine wave signals withdifferent phases. The signal waveforms are not limited to the completesine waveforms, and may be waveforms approximate to the sine waveforms.For example, the transmitting electrode 41 transmits a sine wave signalφA whose phase advances by 45° with respect to a certain referencesignal, and the transmitting electrode 42 transmits a sine wave signalφB whose phase delays by 45°.

When the hole 45 is not present in the vicinity of thetransmitting/receiving electrodes, the signals are shielded by thedetecting wheel 43 grounded electrically so as not to be transmitted.When the detecting wheel 43, however, rotates and the hole 45 comes tothe transmitting electrode 41, a voltage change of the sine wave signalφA between the transmitting electrode 41 and the receiving electrode 44is transmitted as a change in an electrostatic capacity to the receivingelectrode 44. When the rotation of the detecting wheel 43 advances andthe hole 45 comes between the transmitting electrode 41 and thetransmitting electrode 42, both the transmitted signals are synthesized,and the synthesized signal is transmitted to the receiving electrode 44.When the rotation further advances and the hole 45 comes to thetransmitting electrode 42, only the transmitted signal φB from thetransmitting electrode 42 is transmitted.

Since the rotation of the detecting wheel 43 changes the phase of thesignal φC received by the receiving electrode 44 from +45° to −45°, thetime when the phase of the received signal φC passes through 0° withrespect to the reference signal with phase of 0° can be detected as areference position of the detecting wheel 43. A reference position ofthe second hand 48 in a synchronous relationship with the detectingwheel 43 can be, therefore, detected.

Operation control of the watch according to this embodiment is explainedbelow. In this embodiment, the watch is constituted so that hour, minuteand second are indicated by three hands, the second hand is driven by anelectromechanical transducer (motor), and a minute hand and a hour hand(explanation about them is omitted) are driven by anotherelectromechanical transducer (motor). When this embodiment is applied toa watch having an additional function, the second hand indicates notonly second but also calendar information such as day, month and leapyear in a switching manner. Further, the second hand can be used as astopwatch, a timer hand and the like in a switching manner.

A method of attaching the second hand at the time of assembly isexplained. A stem, not shown, is pulled out so as to attain a resetstate. At this time, the electromechanical transducer outputs atransducer driving signal, and a second wheel train fast moves thesecondhand forward per second. After the second wheel train is driven,every time when the hand is moved, the transmitting electrodes 41 and 42output the transmitted signals φA and φB, and the receiving electrode 44receives the received signal φC. The phase of the received signal φC isdetected, and a moment when the phase is changed from an advanced stateinto a delayed state with respect to the reference signal is detected asthe reference position of the detecting wheel 43, and the fast andforward moving of the hand is stopped. Since the detecting wheel 43 andthe fourth wheel 47 rotate synchronously, the reference position of thedetecting wheel 43 can be the reference position of the fourth wheel 47.For this reason, in this state, the second hand 48 is attached to thefourth wheel 47 with the second hand 48 matches the position of zerosecond.

When the second hand 48 is attached and the stem is returned to a 0 stepposition, one pulse of the transducer driving signal is output persecond, and the second hand 48 starts to be moved per second so as toindicate second of current time. IC which controls the entire watchsystem outputs the transducer driving signal, and counts a number usingan electrical counting mechanism, so as to hold the electrical time. Theelectrically held time is started to be counted from a state that thereference position of the second hand 48 is detected, and is reset at60th counting. Every time when the detecting wheel 43 is driven to berotated, detected signals are transmitted from the transmittingelectrodes 41 and 42 and are received by the receiving electrode 44. Ifthe detecting wheel 43 is rotated accurately by the driving signal ofthe IC, the second hand 48 returns to an original position every 60seconds, namely, every one minute, so that the reference position can bedetected. That is to say, the reference position of the second hand 48matches the 0 position of the electrically holding time at every 60seconds.

When the detecting wheel 43, however, does not rotate normally due tothe influence of impact or external magnetic field or is forciblyrotated by an external force, the reference position of the second hand48 shifts from the electrically holding time. When the shift isdetected, the transducer driving signal and the hand position detectedsignal are continuously output, and the detecting wheel 43 is driven torotate fast to a regular direction until the reference position isdetected. In such a manner, the shift of the reference position from the0 position of the electrically holding time is corrected. In thisembodiment, the transducer for driving the second hand 48 and thetransducer for driving the hour and minute hands, not shown, areprovided separately. For this reason, even when the detecting wheel 43which is driven simultaneously with the second hand 48 is rotated to theregular direction, the time information about hour and minute is notshifted.

Even if the reference position of the second hand 48 is temporarilyshifted due to external factors such as impact and magnetic field in thefinished watch, the position of the second hand is corrected every oneminute, and the watch with high display accuracy can be realized.Further, in the case where even if the position of the hand is shifted,it is corrected every one minute, large display hands which may causeshift due to impact can be used.

In the above-mentioned embodiment, the hole 45 is provided on thedetecting wheel 43 made of the metal member, but a constitution composedof a plastic gear and a metal plate as shown in FIG. 7 can be used. InFIG. 7, the detecting wheel 49 is injection-molded by the plasticmaterial, and thus does not have electrical conductivity. A detectingplate 50 made of metal is arranged on the upper surface of the gear ofthe detecting wheel 49 which is press-fitted to the shaft of thedetecting wheel 49. When the detecting wheel 49 rotates and thedetecting plate 50 comes to the vicinity of the transmitting/receivingelectrode, the electrostatic capacity changes between the detectingplate 50 and the transmitting/receiving electrode. For this reason, theposition information can be detected. The manufacturing cost of thisconstitution can be reduced by forming the detecting wheel 49 usingplastic.

Further, a more simplified constitution can be achieved in the followingmanner. A portion of the gear surface of the detecting wheel made ofplastic is plated with metal, or on the contrary, the entire gearsurface other than one portion is plated with metal, and the transmittedsignals are modulated by the rotation of the detecting wheel. Inaddition to the reduction in the cost due to use of the plasticmaterial, the effect due to reduction in the thickness can be expected.

A block constitution of the entire watch system according to thisembodiment is explained below with reference to FIG. 8.

In FIG. 8, the watch system of the present invention has a photocharging power supply including a photoelectric generating element 22and a secondary battery 23. The watch system of the present inventionhas a time reference signal generating circuit 11 composed of a quartzoscillator including a quartz resonator in order to create minimum unittime of the watch time. A dividing circuit 12 divides the time referencesignal output from the time reference signal generating circuit 11, soas to generate a counting time unit signal on a minimum time basis ofthe time holding in the watch. The numeral 21 designates a systemcontrol circuit for controlling the operation of the entire watchsystem. The counting time unit signal generated by the dividing circuit12 is input into a motor driving circuit 14 by control of the systemcontrol circuit 21, and the motor driving circuit 14 drives a pulsemotor in an electromechanical transducing mechanism 15. In the meantime,the counting time unit signal is input into an electrical countingcircuit 13, and the counting time unit signal is counted so that theelectrical time is held. Further, the wheel train mechanism 16 connectedwith the pulse motor of the electromechanical transducing mechanism 15holds the mechanical time information. The mechanical time informationheld by the wheel train mechanism 16 is displayed by the hands of amechanical display mechanism 17.

Sine wave signals with different phases are created by the transmittingcircuit 203 according to control of the system control circuit 21, andare output from the transmitting electrodes 18 and 19 arranged in thevicinity of the wheel train mechanism 16. The transmitted signals 18 and19 are synthesized and modulated so as to be transmitted to thereceiving electrode 20 by the wheel train mechanism 16. The receivingcircuit 200 detects the received signal. Phase of the detected receivedsignal is compared with phase of the reference signal created in thetransmitting circuit 203 at the detecting circuit 202, and themechanical time information which is held by the wheel train mechanism16 is detected according to the compared result. The system controlcircuit 21 controls time synchronization, mis-operation correction ortime setting according to the mechanical time information obtained fromthe detecting circuit 202 and the electrical time information held bythe electrical counting circuit 13. Control information is input intothe system control circuit 21 from an external operating mechanism, notshown, in order to input time information from the outside, and thewheel train mechanism 16 is operated directly and mechanically so as tobe capable of setting the mechanical time.

Concrete configurations of the transmitting circuit 203, the receivingcircuit 200 and the detecting circuit 202 are explained below.

FIG. 9 illustrates an example of a system configuration of thetransmitting circuit 203 for creating a transmitted signal. 71Xdesignates the quartz resonator, and 572 designates a quartz oscillatingcircuit for generating an accurate frequency for creating pitch of theholding time of the watch. The oscillating frequency is a 2¹⁵ Hz. Thenumeral 79 designates an integrated circuit for the electric watchconstitution. 73 designates a ¼ dividing circuit included in theintegrated circuit 79, and it outputs pulse signals Pa and Pb with 2¹³Hz in this embodiment. The phases of both the signals are different fromeach other by π/2. The numerals 74 and 76 designate bandpass amplifyingcircuits for amplifying only a signal with 2¹³ frequency. The circuitconfiguration is such that band eliminating filter circuits composed ofresistors and capacitors are combined with inverter circuits 75 and 77,and a voltage is divided to be attenuated by a resistance voltagedividing circuit. For this reason, signals other than a signal withspecified frequency is attenuated, and only the signal with specifiedfrequency is amplified. The above-mentioned specified frequencyamplifying circuit is combined with the 1/4 dividing circuit, so thatthe sine wave signals φA and φB, amplitude of which is stable and aphase difference between them is fixed, are created from pulse signalsPa and Pb.

FIG. 10 illustrates an example of the receiving circuit composed of anequivalent circuit as modulating means and a pre-amplifying circuit fordetection which is used in the present invention. The transmittingelectrodes 41 and 42 transmit the transmitted signals φA and B which aredifferent from each other. The phase and amplitude of transmittedsignals φA and φB are modulated by a transmission path 86 passingthrough the detecting wheel 43, and the signals are received as thereceived signal φC by the receiving electrode 44. A ground potential andphase are given from electric potential allocation due to a capacitybridge composed of a capacitor on the transmission path 86 to thevoltage of the induced signal φC on the receiving electrode 44.

The received signal φC is, thereafter, amplified by an amplifyingcircuit 87. When the phase is detected, it is necessary to retain onlyphase information, the received signal φC is saturated and amplified soas to become a pulse signal Pc.

FIG. 11 illustrates signal waveforms in the respective circuits. Therelative phase relationship between the respective waveforms aremaintained to be displayed. φ15 designates a voltage waveform at aterminal of the quartz resonator 71 x in the quartz oscillating circuit572 in FIG. 9. P15 designates a pulse signal of 2¹⁵ Hz, namely, 32768 Hzobtained by shaping the sine wave signal of the quartz oscillator, andthis is used also as a clock signal for determining the phase forcontrolling a logic circuit in the electric watch of the presentinvention. The pulse signals Pa and Pb shown in FIG. 9 are created basedon via P15, and the sine wave signals φA and φB of 2¹³ Hz, namely, 8192Hz whose phases are different from each other by π/2 are created via thebandpass amplifying circuits 74 and 76. The frequency can be arbitrarilyselected. Normal watches use the quartz oscillator with 2^(n) Hzaccording to a common specification in the art in order to heightenmass-production effect.

The sine wave signals φA and φB are modulated by the rotating positionof the detecting wheel 43, and the received signal φC (x) (x=1, 2, . . .), whose phase takes a value between the phases of the transmittedsignals φA and φB, is transmitted to the receiving electrode 44. Whenthe detecting wheel 43 rotates to a direction of an arrow in FIG. 6 andthe hole 45 is in the vicinity of the transmitting electrode 41, thereceived signal φC has a waveform of a received signal φC (1) whosephase is close to that of the transmitted signal φA. When the hole 45comes to the vicinity of the transmitting electrode 42, the receivedsignal φC has a waveform of a received signal φC (2) whose phase isclose to the transmitted signal φB. The phase of the received signal φCchanges in such a manner. Further, when the hole 45 of the detectingwheel 43 is not in the vicinity of the transmitting/receivingelectrodes, the transmitted signals φA and φB are shielded by thedetecting wheel 43 so as not to be transmitted to the receivingelectrode 44. A received signal φC (3)has a waveform with few amplitudeincluding only a noise component.

Since the received signal φC (3) at this time is noise signal without aphase component necessary for the position detection, it is cut by asquelch circuit, detailed later. Since the received signal φC (x)including the phase information is transmitted by a change in theelectrostatic capacity between the electrodes, it's amplitude is verysmall, but its phase information is held. The received signal φC (x) isamplified so as to be saturated by the amplifying circuit 87 shown inFIG. 10 and becomes to be a rectangular detected signal Pc (x) (x=1, 2,. . . ).

The system for detecting the received signal is explained below.

FIG. 12 is a circuit diagram illustrating a detecting circuit fordetecting the phase of the received signal. FIG. 13 is a waveform chartof a signal representing the detected result as an output of thedetected result. The detecting circuit shown in FIG. 12 changes anoutput voltage of the phase detecting circuit according to whether thephase of the received signal modulated by the detecting wheel 43advances or delays with respect to the phase reference signal as thereference of the phase detection.

In FIG. 12, a pulse signal Pab with phase just in the middle between thephases of the signals Pa and Pb shown in FIG. 11 is input to a datainput flip-flop 216 as clock signal thereof which is a reference signal.The reference signal Pab is created easily from the transmitted signalsPa and Pb. On the other hand, the detected signal Pc (x), which isobtained by amplifying and saturating and shaping the received signal φC(x), is input to the flip-flop 216 as a data signal. The flip-flop 216outputs a detected result signal Sens-Out with a rise of the clocksignal Pab being used as a trigger.

When the phase of detected signal Pc (x) advances further than that ofthe reference signal Pab like the signal Pc (1) shown in FIG. 11, a Hlevel “1” of the detected result signal Sens-Out is output. When thephase of the detected signal Pc (x) delay from that of the referencesignal Pab like the received signal Pc (2)the level of the detectedresult signal Sens-Out is switched into an L level “0”. The timing atwhich the H level of the detected result signal Sens-Out is switchedinto the L level can be detected as the reference position of thedetecting wheel 43.

A phase detecting system which is different from the above one isexplained below.

The logic circuit as the pulse generating means generates a chargeinstructing signal P-crg and a discharge instructing signal P-dcrg shownin FIG. 11 from the detected signals Pc (1), Pc (2)and the referencesignal Pab. Since the phase of the received signal Pc (1)advancesfurther than that of Pab, and the phase of the received signal PC(2)delays from that of Pab, the following relationships are established:

$\begin{matrix}{{P\text{-}{crg}} = {\lbrack{Pc}\rbrack\bigcap\left\lbrack {/{Pab}} \right\rbrack}} \\{\mspace{65mu}{= {\lbrack{Pc1}\rbrack\bigcap\left\lbrack {/{Pab}} \right\rbrack}}} \\{{P\text{-}{dcrg}} = {\left\lbrack {/{Pc}} \right\rbrack\bigcap\lbrack{Pab}\rbrack}} \\{\mspace{79mu}{= {\left\lbrack {/{Pc2}} \right\rbrack\bigcap\lbrack{Pab}\rbrack}}}\end{matrix}$:(∩ represents logical OR, and/represents logic inversion) The frequencyof the transmitted signal is 2¹³ Hz, namely, about 8 kHz, and a storagecapacitor of small capacity is charged to a plus side via the resistorat the H level “1” of P-crg. The capacitor is discharged to a minus sidevia the resistor at the H level “” of P-dcrg. The time constant of thecapacitor is set to be larger than a cycle of 8 kHz by one digit, andthe phase information of the received signal with respect to thetransmitted signal is obtained as the voltage of the capacitor.

When the phase of Pc advances further than the Pab, the signal P-crg of“1” is obtained, and its pulse width becomes large in proportion to thephase difference, so that the capacitor is charged and the voltage ofthe capacitor is saturated to the plus side.

On the contrary, the phase of Pc delays from the Pab, the signal P-dcrgof “1” with a pulse width proportional to a delayed phase is obtained,and electric charges of the capacitor are discharged to the minus side,so that the voltage of the capacitor becomes zero. In such a manner, thephase change of the detected signals is converted into the voltagechange of the capacitor so as to be read, and the reference position isdetected.

FIG. 15 illustrates a concrete example of the phase detecting circuitusing the capacitor.

In FIG. 15, a gate 91 charges the capacitor 92 for storing electriccharges into the plus side via the resistor 93. The condition that theswitch element 94 for setting a charging condition is turned on is asfollows:

{detected output: Pc=H} &

{phase reference signal: Pab=L} &

{non-squeltch:/Scl−out=H}=H.

A logical level of the gate 91 becomes L, and a P channel FET 94 (fieldeffect transistor) is turned on so that the capacitor 92 is charged viathe resistor 93. The AND operation is explained as follows. Thenon-squelch:/Scl−out=H represents that the hole is present in thevicinity of the detecting electrode. The phase reference signal: Pab(ωt)=L and the detected output: Pc=H represent that the phase of thedetected output advances with respect to the phase reference signal.That is to say, this means that the hole 45 is close to the transmittingelectrode 41 in FIG. 6.

Similarly the discharging condition of the capacitor 92 is that a gatepotential of the N channel transistor 96 is set to an H level. Thecondition that an output of the gate 95 becomes the H level is asfollows:

{detected output: Pc=L} &

{phase reference signal: Pab=H} &

{non-squelch: /Scl−out=H}=H.

When the FET switch 96 is turned on, discharge is carried out via theresistor 97 The condition at this time is such that the hole is in thevicinity of the detecting electrode and the phase of the detected Outputis delayed from the phase of the phase reference signal. That is to say,the rotation of the detecting wheel 43 continues, and the hole 45 isclose to the transmitting electrode 42 in FIG. 6.

The gates 91 and 95 are advance/delay detecting means which detect thatthe amplitude of the detected signal Pc is at a constant level, anddetect whether the phase of the received signal Pc advances or delayswith respect to the phase reference signal Pab so as to output theresult. The FET switches 94 and 96 are charge/discharge switching meanswhich switch the charge/discharge state according to the outputs fromthe gates 91 and 95 as the advance/delay detecting means.

In the actual constitution, the resistor 93 and the switch element 94are united, and an ON resistor of FET as the switch element 94 isdesigned so as to have a suitable value, thereby eliminating theresistor 93. Similarly, the function of the resistor 97 is included inthe ON resistor of FET for discharge as a switch element 96. Acomparator 101 compares a voltage Vcrg of the capacitor 92 and areference voltage value Vref which is divided by the resistors 98 and99. When Vcrg≧Vref, an H level of a detected result signal Senc_out isoutput as a logic output via a Schmitt circuit 100.

FIG. 14 illustrates the voltage Vcrg of the capacitor 92 with respect tothe rotating angle of the detecting wheel 43. When the rotation of thedetecting wheel 43 proceeds and the hole 45 adjoins the transmittingelectrode 42, the capacitor is charged, and the voltage Vcrg is changedfrom an “L” state into an “H” state with respect to a comparisonreference voltage 111. Thereafter, the hole 45 passes through the middleportion between the transmitting electrodes 41 and 42, the electriccharge storage capacitor 92 is discharged so that the voltage is againchanged into “L”.

All mechanical dimensions of the wheel train in the watch includeerrors, and clearance is present in an up-down direction and in arotating direction of the gear. For this reason, the detected voltageVcrg greatly changes and also the phase changes slightly according tobacklash of pulse motor driving and a direction of the watch. Asexamples, a curve 112 in FIG. 14 represents a voltage when the watchfaces upward, and a curve 113 represents a voltage when the watch facesdownward.

As for the phase detected information, when the detected voltage Vcrg islow, an error signal is generated due to an influence of an noise. Thatis to say, there is a big possibility in that when the capacitor 92 ischarged, the timing at which voltage of the capacitor changes from “L”to “H” with respect to the comparison reference voltage 111 is shifted.When the detected voltage Vcrg is, however, high, it is possible toobtain accurate position information. In a range, therefore, where thedetected voltage Vcrg is changed from “H” to “L” in the vicinity of thehole center, namely, when the detected voltage Vcrg is high, thedetection is hardly influenced by noise so that accurate positioninformation can be obtained. A point 114, therefore, where Vcrg ischanged from “H” into “L” is hardly changed due to a difference in theposture of the watch and the like, and thus it is effective that thistiming is read as the reference position.

In FM broadcasting system, when a radio wave from a far broadcastingstation becomes weak, the noise increases. In order to prevent thisproblem, a squelch circuit is provided in a FM receiver, and a thresholdvalue of the squelch circuit is set to a received signal level in an FMreceiver. And this squelch circuit suppresses a detected output having alevel not higher than the threshold value. The present invention is usedfor transmitting and receiving a signal between electrodes in a closedistance in the watch, but the squelch circuit is provided in order tosuppress a noise when a pattern hole for detection of the detectingwheel 43 is in a position other than the periphery of the detectingelectrodes.

The above-mentioned squelch circuit outputs a squelch signal in responseto a received signal level. In another effective method, the squelch isattained by a time gate whereby a time at which next hole position isdetected is predicted based on the timing with which the hole positiondetected signal is securely captured and masks input signals input forthe periods up to the predicted time.

In the constitution of the present invention, the information about thephase measured result represents the hole position of the gear of thewheel train to be measured, and after the pulse motor for driving thewheel train is driven, the rotating position of the wheel train can bemeasured securely only once in every time of the measurement. It is notalways necessary to measure the hole position continuously. The detectedinformation which is obtained by the most simplified detecting system inthe present invention is 1 bit, and it represents whether or not therotating angle of the hole position of the wheel train gear exceeds aspecified angle at specified time. In order to define the angle of thewheel train gear, therefore, the counting number is reset, and theelectric counting circuit and the pulse motor for driving the wheeltrain are driven in parallel by one rotation of the gear, and positiondetected data are stored by using the counted value of the electriccounting circuit as an address. Thereafter, the hole position as theresult can be determined according to the pattern of the data withrespect to the address.

The contents of the measurement are briefly explained as follows. Theposition is measured intermittently from a state in which the patternhole for detection is not present in the vicinity of the detectingelectrode. The rotating angle of the wheel train is measured in thefollowing procedure. Wait state information until the pattern hole fordetection reaches the detecting electrode is detected. An L level of thedetected data obtained from a time when the pattern hole for detectionis arrived at the detecting electrode to a time when the center of thepattern hole for detection is detected. A change of the detected datafrom the “L” level into the “H” level at the center of the pattern holefor detection is detected. Thereafter, maintenance of the H levelaccording to the movement of the gear is confirmed, and the wait stateinformation for the period from passing of the pattern hole fordetection over the detecting electrode to the original rotating positionis detected.

In order to measure the hole center position, it is necessary thatpresence of the detecting electrode in the vicinity of the hole positionis measured and the angle position of the wheel train in the vicinity ofthe hole is measured finely. In order to decide the position thereoffrom the entire image of the measured data, a circuit which make adetermination based on an amplitude component of the detected signalthat the measured data has less noise and represents “a non-wait state”in that the phase detected information serve as important data or acircuit which stores a certain wait time zone after the phase detectingcircuit changes the output logic value as wait time zone in the electricwatch is required. A non-squelch signal {/Scl−out} gate signal isgenerated based on the amplitude detected signal or the time zone signalof the electric watch.

FIG. 16( a) illustrates one example of the amplitude detecting circuitfor suppressing noise in order to generate the non-squelch signal{/Scl−out}. An amplifying circuit 132 with constant amplification factoramplifies the weak received signal φc. The amplifying circuit 132 ismultiplied by negative feedback of 1/K due to resistance potentialdivision so that the amplification factor becomes K times as large asthe original amplification factor regardless of ambient temperature andpower supply voltage.

The threshold value, which is the reference of the amplificationcomparison, is determined by a threshold value and carrier mobility ofan FET 133 and is slightly larger than the threshold value of the FET133, and temperature characteristics of the threshold value andtemperature characteristics of the mobility are compensated by eachother. A resistor 134 determines a current level of the chargingoperation of the FET 133, and a resistor 135 determines a current levelof discharge. When K×(a crest value) of the received signal φC of ACinput exceeds the threshold value of the FET 133, the capacitor 136starts to be charged. When discharge resistance 135 is set to besufficient large, the capacitor 136 is charged with electric charges ina sampling manner according to the crest value which exceeds thethreshold value of the FET 133, and the electric charges are held fortime corresponding to about electrical discharge time constant.

A comparing circuit 139 compares the voltage Vcrg of the capacitor 136due to the electric charges stored in the capacitor 136 with the voltageVscl obtained by dividing the power supply voltage using the resistors137 and 138. A logic value of the result is stored in a latch circuit140 in a cycle of the transmitted signal. In such a manner, thediscrimination of the crest value component of the AC detected signaland the generation of the non-squelch signal (/Scl−out) can be realized.A source supply potential on a source side of the FET 133 can be aperiodically fluctuating threshold value by applying a pulse of thereference signal Pab instead of a +DC power supply voltage or a voltageobtained by dividing the sine wave voltage from which harmonic of Pab isremoved. The removal of the harmonic can be realized by a circuitsimilar to the bandpass amplifying circuit 74 in FIG. 9 where an inputdividing circuit is combined with a selection amplifying circuit.

The constitution of FIG. 16( a) is represented by a functional block asshown in FIG. 16( b). In FIG. 16( b), the amplifying circuit 142 withconstant amplification factor amplifies the received signal φC accordingto constant magnification, and the detecting circuit 143 extracts anamplified component. The comparing circuit 144 compares the receivedsignal φC with the reference voltage generated by a reference voltagegenerating circuit 147 so as to detect that the received signal φC hasan amplitude not less than the set amplitude. A latch circuit 145latches the output signal of the comparing circuit 144, and outputs anon-squelch signal (/Scl−out) which represents that the phase detectedoutput has meaning.

FIG. 17( a) illustrates another example of the amplitude detectingcircuit for generating the non-squelch signal {/Scl−out}. An amplifyingcircuit 169 with constant amplification factor amplifies the weakreceived signal C. The amplitude threshold value comparison value isobtained from reference signal Pab, and this amplitude threshold valuecomparison value, namely, the fluctuation threshold value, is obtainedby dividing Pab using by resistors 151 and 152. A slightly complicatedcircuit for replacing a signal by a signal obtained by removing harmoniccomponent from Pab obtains a rational threshold value. A comparisonamplifying circuit 153 compares a signal voltage obtained from theamplifying circuit 169 with the fluctuation threshold value, and a diode154 rectifies the signals, and a circuit having the discharge timeconstant determined by a capacitor 155 and a resistor 168 temporarilyholds the result. A latch circuit 156 stores the result as a logic valuethereinto and outputs a non-squelch output (/Scl−out) using a signal Pbas a clock.

The constitution in FIG. 17( a) is represented by a functional block asshown in FIG. 17( b). In FIG. 17( b), K·φC is obtained in such a mannerthat an amplifying circuit 161 with K-times constant magnificationamplification factor amplifies the received signal φC so as to obtain asignal K·φC, and a comparison reference voltage Vref is generated by areference voltage generating circuit 164. K·φC and the comparisonreference voltage Vref are input into a comparison amplifying circuit162, and the input signal is amplified and the saturated signal isoutput. The amplified signal is detected by a detecting circuit 163, andis temporarily stored in a latch circuit 165 so as to be output as anon-squelch output (/Scl−out).

The position detecting system in the above-explained example isconstituted so that the amplitude of the received signal φC is detected,a detection is made that the hole is close to the transmitting/receivingelectrode, and the accurate position is detected by the phaseinformation of the received signal φC. The position thereof can be,however, detected by either one of the detection of the phase and thedetection of the amplitude. In this case, the reliability of theposition detection is deteriorated due to a noise or the like, but thecircuit configuration can be simplified.

One of main points in the constitution of the present invention is thatthe influence of the clearance in the mechanism is suppressed by thedifferential operation using a plurality of transmission paths.

According to the above viewpoint, FIG. 18( a) represents sets of theamplitude voltages of a φC component {P1, Q1} and {P2, Q2} which are onup and down positions with respect to an axis of the amplitude 0 and inwhich the rotating angle is read along the lateral axis. Note that wheneach one of the transmitting signals φA and φB is independentlytransmitted through a single transmission path, respectively, and the φCcomponent corresponds to the transmitted signals φA and φB and is takenout from the received signal φC, and a set of the amplitude voltage ofthe φC component corresponding to the transmitted signals φA and φB isdetermined as {P1, Q1} and {P2, Q2}, respectively. Jolting of the geardue to the clearance in axial direction differs depending on thepostures of the wrist watch, for example, like the sets of the amplitudeof the received signal {P1, Q1} and {P2, Q2}. When, therefore, thedetected voltage is sliced on a single transmission path at a constantslice level, detecting angles of P1 and P2 (=rotating angle where theslice level match the detecting level) show different values accordingto the postures of the wrist watch.

FIG. 18( b) is a graph where the differences in FIG. 18( a) arecalculated. In the drawing, D1=P1−Q1 ., and D2=P2−Q2. As to D1 and D2,the rotating angles at the zero cross point where the difference outputsignal switches a symbol become equal with each other, and thus thedifferential detecting method reduces the influence of the jolting ofthe wheel train.

Another constitution which suppresses noise and improves the reliabilityof the position detection is explained below. In a signal which isobtained by amplifying and saturating the received signal φC withoutsuppressing noise, its internal noise is also amplified to a saturatinglevel. For this reason, a spike-shaped noise signal is generated. When,however, the measurement is carried out successively three times, forexample, and a majority logic of the obtained three signals is output,the spike-shaped noise is eliminated. Since the wheel train gear may bemeasured after the intermittent driving of the motor in the watch, inthe actual position detection, the signal is sampling-detectedintermittently.

Another constitution for eliminating noise is explained. The detectedsignal, which is obtained by amplifying the received signal φC includingnoise, becomes a pulse signal including a spike-shaped noise. The pulsetype detected signal is allowed to pass through a low-frequency filtercomposed of a publicly-known approximate integrating circuit, and thespike noise component is eliminated so that P0 (θ) is obtained. Further,the latch circuit creates PΔ (θ) which is delayed by certain short timeΔt logically.

When AND of inverted signals of P0 (θ) and PΔ (θ) is designated by Pdet:Pdet=P0(θ)·{/PΔ(θ)}Pdet becomes a pulse with width Δt which match a rise where the signalwith narrow width from which the spike noise is eliminated is changedfrom the “L” level into the “H” level. This pulse gives the angle of thehole center position. When the low-pass filter can eliminate the spikenoise sufficiently, the circuit for detecting the hole position can besimplified greatly. Suppression of noise by means of creation of awindow function and a squelch signal can be omitted.

The above example uses the signals having different phases and samefrequency as the transmitted signals, but can use signals with differentfrequencies in a synchronous relationship.

FIG. 19 is a diagram illustrating an example when the frequencies in thesynchronous relationship are adopted.

In this example, 16,384 Hz is adopted as φA, and 8,192 Hz is adopted asφB. φA is input into the transmitting electrode 41 and φB is input intothe transmitting electrode 42, and the received signal is taken out fromthe receiving electrode 44 via the detecting wheel 43.

When the hole 45 of the detecting wheel 43 is on the side of thetransmitting electrode 41, as shown in FIG. 19( a), φC which is close toφA is obtained from the receiving electrode 44. When the hole 45 of thedetecting wheel 43 is in the middle between the transmitting electrodes41 and 42, φC shown in FIG. 19( b) is obtained. When the hole 45 of thedetecting wheel 43 is on the side of transmitting electrode 42, as shownin FIG. 19( c), φC which is close to φB is obtained from the receivingelectrode 44.

An output change from the receiving signal 44 is detected, and the phaseof the output change is compared with the phase of the reference signalso that the position of the detecting wheel 43 can be detected.

In this case, the position of the detecting wheel 43 may be detectedbased on the phase and the amplitude of the detected signal.

FIG. 20 is a diagram for explaining the timing of the measurement of thewheel train gear position. At a moment when the pulse motor of the watchis driven, extremely large instantaneous power which is 1000000 times aslarge as an average power is consumed in the watch system of low powerconsumption. For this reason, while and just after the motor is driven,a voltage of a galvanic cell in the power supply fluctuates. At themoment of the driving, large electromagnetic noise is generated. Theoperation for the position detection according to the weak electricfield detection in the present invention should be performed in such amanner that the operation is sufficiently separated from the motordriving phase, namely, in margin for time.

When disturbance due to the internal noise in the amplifying circuit isconsidered for the measurement of the weak electric field, it isnecessary that the position measurement is carried out at plural times,and the measured results are processed by the majority logic circuit sothat the most probable value is estimated. The measurement in FIG. 20 isan example of the timing chart in the case where the position ismeasured at odd number of times when certain time passes after the motoris driven. The detecting position is determined by majority of thedetected results of the measurement at odd number of times at timingwhere the noise generating range is avoided.

The above embodiments explain the constitution for detecting theposition of the time information by means of the driving wheel train,but as another embodiment, this constitution can be applied also to thedetection of the information about the calendar display position. FIG.21 is a plan view for explaining the constitution for detecting theposition of the day plate 301 for displaying day. In FIG. 21, days from1 to 31 are printed on the surface of the day plate 301, and one day isdisplayed through a window hole 302 of a dial plate.

In FIG. 21, a day of 1 is displayed. The rotation of the motor in theelectromechanical transducer, not shown in the day plate 301, istransmitted to the day plate 301, so that the day plate 301 rotates byone display in one day. The transmitting electrodes 303 and 304 arearranged on the upper surface of the printed position of 3 and 4 on theday plate 301, and the receiving electrode 305 is arranged on the lowersurface in an opposed manner. The day plate 301 is made of a plasticmaterial, and a metal film is applied to its lower surface so as to begrounded with a watch move. The lower surface of the printed position of4 has a circle 306 which is a non printing portion.

In the state of FIG. 21, only the signal from the transmitting electrode304 is transmitted to the receiving electrode 305, and the signal fromthe transmitting electrode 303 is shielded by the day plate 301 so thatthe signal from the transmitting electrode 303 is not transmitted to thereceiving electrode 305. When the day plate 301 once rotates and 2 isdisplayed through the window hole 302, the circle 306 moves to thetransmitting electrode 303, so that only the signal from thetransmitting electrode 303 is transmitted to the receiving electrode305. A change of the signals transmitted to the receiving electrode 35is read, so that a reference position of the day plate 301 can bedetected. As shown in the drawing, when the position detection of theday plate 301 is executed in a day position different from that of thewindow hole 302, the detection can be executed without influencing theday display.

When positions of the day plate, a month plate and a year plate in thewrist watch can be confirmed, the wrist watch including a perpetualcalendar, which does not require month-end date correction, can berealized by a simple mechanism. The detecting timing may be limited toaround midnight. A detecting angle allowable error is large. Amplitudedetection and impedance detection using two or one transmittingelectrode(s) can be, therefore, utilized. At the initial setting in awrist watch to be corrected by a radio wave, an electric time system isrewritten instantaneously based on the received information, andmechanical time should be synchronized with the electric time.

It takes a lot of time to correct date, hour and minute by rapidtraverse of second, but when second, hour and minute, and date arecorrected in three blocks in parallel, the initial storage setting canbe realized extremely quickly. Since such great time shift occurs aboutonce in a several years, namely, the frequency is low like just afterconnection of a power supply battery, a simple method may be used. Inthis method, while hour, minute and second are driven at high speed, thedetection on the transmitting and receiving electrodes of the wheeltrain is made successively, and a code hole inscribed on the gear isoptically read as a time series code.

As is clear from the above explanation, in the first example of thisapplication, it is preferable that the transmitting circuit has afunction for shaping a plurality of transmitted signals in which theelectric field is used as a carrier. Further, it is desirable that thereceiving circuit has a function for amplifying the received signal.

On the other hand, it is preferable that the detecting circuit of thepresent invention has a function such that the received signal receivedby the receiving circuit detects mechanical position information of thesignal modulating member according to electric field propagatingproperties such that the electric field is propagated in a certain placebut is not propagated in another place.

Further, the detecting circuit of the present invention is the phasedetecting circuit, and it is desirably constituted so as to detect themechanical position information of the signal modulating memberaccording to the phase information of the received signal modulated bythe modulating member. Moreover, the detecting circuit may be theamplitude detecting circuit, and in this case, it is desirablyconstituted so as to detect the mechanical position information of thesignal modulating member according to signal intensity information ofthe received signal modulated by the signal modulating member.

In the present invention, the detecting circuit includes both the phasedetecting circuit and the amplitude circuit, determines the detectingrange of the mechanical position information of the modulating memberbased on the signal intensity information of the received signalmodulated by the signal modulating member. Further the detecting circuitis desirably constituted so as to detect the position information of thesignal modulating member based on the phase information of the receivedsignal modulated by the signal modulating member. The plural transmittedsignals may be signals with different phases and same frequency.

In the present invention, the transmitted signals may be signals withdifferent frequencies in the synchronous relationship.

In the present invention, it is desirable that a plurality of thetransmitted signals have sine waves or waveforms approximate to the sinewave.

On the other hand, in the present invention, it is desirable that thephase detecting circuit is configured so as to change a voltage of thephase detected output according to the states in which the phase of thereceived signal modulated by the modulating member advances or delayswith respect to the phase reference signal which is the reference of thephase detection.

For example in the present invention, one of the preferable examples issuch that the phase detecting circuit has a delay/advance detectingmeans, a charge/discharge switching means and a voltage detecting means.The delay/advance detecting means detects the delay or advance of thephase of the received signal with respect to the phase reference signalto be the reference of the phase detection, and outputs a pulse signalwhose pulse width is a phase difference between the phase referencesignal and the received signal. The charge/discharge switching meanscharges a capacitor with electric charges whose amount is proportionalto the pulse width of the pulse signal according to delay/advanceoutput, or discharges the capacitor at an electric charge amountproportional to the pulse width of the pulse signal. The voltagedetecting means compares a terminal voltage of the capacitor with apredetermined voltage so as to output the compared result.

In the present invention, the signal modulating member may beconstituted so that its shape or some of the components have/hasconductivity or permittivity different from those of another portions.Further, the signal modulating member is made of a conductive metalmaterial, and may have a hole, or its one portion having a notch or aconvexo-concave shape.

In the present invention, the signal modulating member is made of anon-conductive member such as plastic and a conductive metal material,and one portion of the metal material may have a hole, a notch, or aconvexo-concave shape. Further, the signal modulating member is made ofa non-conductive member such as plastic, and one portion of thenon-conductive member may be plated with metal.

The signal modulating member of the present invention may be composed ofa part of the wheel train for transmitting the rotation driven by theelectromechanical transducer to the rotating member to be measuredhaving a hand display function. It is desirable that the signalmodulating member is constituted so as to have a mechanism for detectingthe reference position of the rotating member to be measured by themechanical position information of the signal modulating member.

Meanwhile, as another example of the present invention, the signalmodulating member is composed of a part of the wheel train fortransmitting the rotation driven by the electromechanical transducer tothe rotating member to be measured having the date display function orthe date indicator. The signal modulating member may be constituted soas to have the month-end automatic correcting function for detecting thereference position of the rotating member to be measured or the dateindicator based on the mechanical position information of the signalmodulating member and automatically eliminating a month-end nothing dayin even month based on the electric calendar information held in thewatch circuit.

The transmitting electrode and the receiving electrode of the presentinvention may be arranged in an opposed manner so as to sandwich themodulating member. Further, the transmitting electrode and the receivingelectrode may be arranged in the opposed manner on the one surface ofthe modulating member.

On the other hand, a single or plural number of the transmittingelectrode may be arranged, or a single or plural number of the receivingelectrode may be arranged.

In the present invention, a reference signal generating circuit may beprovided so as to generate a reference signal for detecting the positioninformation of the signal modulating member based on the pluraltransmitted signals output from the transmitting circuit. The signalmodulating member may modulates the phase or the frequency of thetransmitted signals.

As explained based on the first example, the mechanical positioninformation of the wrist watch can be detected by non-contact, lowcurrent, low voltage, small space and low cost, and the electric watchwith high reliability with less deterioration with time can be provided.Further, a wrist watch with high reliable holding time, a radio wavecorrecting wrist watch with a short-time time correcting function, and awrist watch with month-end automatic correcting function can berealized. Further, an electric field detecting type thin wheel trainposition detecting mechanism, which has been required but could not berealized, can be realized by the differential detecting method using aplurality of the transmission paths for passing of the wheel train ofthe present invention in order to use large hands.

Further, according to the present invention, in the method of directlydetecting a single electric field which is conventionally considered,since a principle that a change in spacial intensity of the electricfield is detected is utilized, a change in the space dependenceintensity of the electric field is smooth. As a result, a specifiedpoint of the wheel train cannot be detected finely. Since the watchposture difference dependence of the electric field intensity due to theclearance of the wheel train is large, this prior art method cannot beused for the position detection. Such problems are solved in thedifferential detecting system on the plural transmission path accordingto the present invention. Particularly a difference of the phases isutilized, the phase detecting circuit is provided so that amplitude orpolarity of the detected signal can cross zero when the signal passesthrough a specified point. As a result, a design in which the spaceposition is detected finely can be provided. Further, the influence ofthe difference in the postures of the watch can be reduced by thedifferential detection.

SECOND EXAMPLE

FIGS. 22 to 24 are diagrams for explaining a second example of thepresent invention.

In the second example, the arrangement and the constitution of thetransmitting electrode, the rotor and the receiving electrode are thesame as those shown in FIG. 2 of the first example. Further, thearrangement and the constitution of the fourth wheel, the fifth wheeland the detecting wheel are the same as those shown in FIG. 6 of thefirst example. The waveforms of the respective portions are, therefore,same as those shown in FIG. 11.

That is to say, the basic technical constitution of the electric watchof the second example is as follows. The electric watch having thedetecting mechanism for detecting the position information of therotating member to be measured includes a transmitting circuit, thetransmitting electrode, signal modulating means, the receivingelectrode, a receiving circuit, a reference signal generating circuitand a detecting circuit. The transmitting circuit generates a pluralityof transmitted signals. The output signal from the transmitting circuitis applied to the transmitting electrode. The receiving electrodereceives a signal from the transmitting electrode. The rotor is providedbetween the transmitting electrode and the receiving electrode, andmodulates the transmitted signal output from the transmitting electrode.The modulated signal received by the receiving electrode is input to thereceiving circuit. The reference signal generating circuit generates areference signal for detecting the position information of the rotorbased on the transmitted signals output from the transmitting circuit.The detecting circuit compares the output signal from the receivingcircuit with the reference signal from the reference signal generatingcircuit so as to detect the mechanical position information of therotor.

The position detecting system in the electric watch according to thesecond example of the present invention is explained with reference toFIG. 22.

In FIG. 22, the position detecting system is composed of a transmittingcircuit 220, signal modulating means 230, a receiving circuit 240, areference signal generating circuit 250, and a detecting circuit 260.The transmitting circuit 220 includes two bandpass filter amplifyingcircuits (hereinafter, BPF amplifying circuits) 221 and 222. The signalmodulating means 230 includes transmitting electrodes 231 and 232, arotor 233 having a hole portion 234, and a receiving electrode 235. Thereceiving circuit 240 includes an amplifying circuit 241. The referencesignal generating circuit 250 includes capacitors 252 and 253 and anamplifying circuit 251.

A connecting relationship in the position detecting system of FIG. 22 isexplained below.

In the electric watch, an output terminal of an output pulse Pa (+45°)of an oscillation dividing circuit 210 is connected with an inputterminal of the BPF amplifying circuit 221 in the transmitting circuit220. An output terminal of an output pulse Pb (−45°) in the oscillationdividing circuit 210 is connected with an input terminal of the BPFamplifying circuit 222 in the transmitting circuit 220. Further, anoutput terminal of the BPF amplifying circuit 221 is connected with thetransmitting electrode 231 of the signal modulating means 230 and oneterminal of the capacitor 253 in the reference signal generating circuit250. An output terminal of the BPF amplifying circuit 222 is connectedwith the transmitting electrode 232 of the signal modulating means 230and one terminal of the capacitor 252 in the reference signal generatingcircuit 250. The receiving electrode 235 is connected with an inputterminal of the amplifying circuit 241 in the receiving circuit 240. Anoutput terminal of the amplifying circuit 241 is connected with a signalinput terminal of the detecting circuit 260. An output terminal of theamplifying circuit 251 in the reference signal generating circuit 250 isconnected with a detecting input terminal of the detecting circuit 260.

The oscillation dividing circuit 210 includes a quartz oscillatingcircuit for oscillating according to the reference oscillating frequencyφ15 shown in FIG. 11. The reference oscillating frequency φ15 isconverted into the pulse signal P15 so as to be used as the referencesignal source. The pulse signal P15 is divided by a publicly-knowndividing circuit, so that two output pulses Pa (+45°) and Pb (−45°)whose phases shift from each other by π/2 (hereinafter, Pa (+45°) isdesignated by Pa, and Pb (−45°) is designated by Pb. Pa is applied tothe input of the BPF amplifying circuit 221 of the transmitting circuit220, and Pb is applied to the input of the BPF amplifying circuit 222 ofthe transmitting circuit 220. As a result, the transmitted sine wavesignals φA and φB whose phases are different from each other by π/2 aregenerated.

The transmitted sine wave signal φA is transmitted from the transmittingelectrode 231 of the signal modulating means 230, and the transmittedsine wave signal φB is transmitted from the transmitting electrode 232of the signal modulating means 230. The received sine wave signal φCwhich is received by the receiving electrode 235 becomes a signal whichis modulated according to a change in the position relationship betweenthe hole portion 234 and the transmitting electrodes 231 and 232 due torotation of the rotor 233.

The received sine wave signal φc is modulated according to the change inthe position relationship between the hole portion 234 and thetransmitting electrodes 231 and 232 due to the rotation of the rotor233. Since this state is already explained in the first example withreference to FIG. 11, the detailed explanation thereof is omitted.

The received sine wave signal φC is amplified so as to be saturated bythe amplifying circuit 241, the amplified signal becomes a receivedsignal Pc having phase information. The received sine wave signal φC asshown in FIG. 23( a) is indicated as a received signal φC(1) in FIG. 11,and the received sine wave signal φC as shown in FIG. 23( c) isindicated as a received signal φC(2). The received signal φC isamplified by the receiving circuit 240 so as to become a signal Pc, andthe phase of the signal Pc is detected by the detecting circuit 260.

In the reference signal generating circuit 250 for generating thereference signal Pab for detection, the transmitted sine wave signal φAfrom the BPF amplifying circuit 221 of the transmitting circuit 220 isinput into the capacitor 253 of the reference signal generating circuit250. Further, the transmitted sine wave signal φB from the BPFamplifying circuit 222 is input into the capacitor 252. The capacitiesof the capacitors 252 and 253 are equal with each other, so that, thesine wave with the phase which is just intermediate between thetransmitted sine wave signals φA and φB is input into the input terminalof the amplifying circuit 251 and is amplified so as to be saturated bythe amplifying circuit 251. As a result, the reference signal Pab ofFIG. 11 can be obtained.

When a pulse signal, which is obtained by dividing the pulse signal P15of the oscillation dividing circuit 210, is used as the reference signalPab, the phase of the reference signal Pab does not change due totemperature condition and the like. The phases of the transmitted sinewave signals φA and φB, however, change due to the temperaturecharacteristics of the EPF amplifying circuits 221 and 222 in thetransmitting circuit 220. Therefore, the phase of the received sine wavesignal φC changes and the phase of the received signal Pc also changes,as a result, a phase difference between the received signal Pc and thereference signal Pab changes due to the temperature condition. In orderto prevent this, in the present invention, the reference signalgenerating circuit 250 generates a reference sine wave signal φab basedon the transmitted sine wave Outputs φA and φB so that the referencessignal Pab is obtained. The received sine wave signal φc and thereference sine wave signal φab are generated from the transmitted sinewave signals φA and φB. Further, the amplifying circuit 241 of thereceiving circuit 240 for outputting the received signal Pc and theamplifying circuit 251 of the reference signal generating circuit 250for outputting the reference signal Pab have the same circuitconfiguration, the relationship 6 f the phases in both signals are notchanged so that the phases change relatively and uniformly even if theyare influenced by the temperature. For this reason, the phaserelationship between the signals do not change.

Since the detecting operation of the received signal Pc in this exampleis the same as that in the first example, the detailed explanation isomitted.

FIG. 24 is a block diagram of the entire electric watch using theposition detecting system of the present invention. In FIG. 24, thepower supply, such as a solar cell for light power generation and asecondary battery for charging light power generating energy provided inthe electric watch are omitted.

In FIG. 24, the oscillation dividing circuit 210 including the quartzoscillating circuit as the reference signal source of the watch isprovided, so as to output a plurality of counting time signals. Thecounting time signals are input into the motor driving circuit 14 bycontrol of control means 21A including a microcomputer for controllingthe entire electric watch. Further, the counting time signal is countedso as to be input also into the counting circuit 13 for holding theelectric time. When the motor driving circuit 14 operates, the pulsemotor 15 rotates in a stepped manner, and the mechanical timeinformation is held by the wheel train mechanism 16 connected with thepulse motor 15. As a result, the time is displayed by the hands of thedisplay means 17.

The output pulses Pa and Pb whose phases are different by π/2 outputfrom the oscillator dividing circuit 210 are input into the transmittingcircuit 220 directly or via the control means 21A. The output pulses Paand Pb are converted into the transmitted sine wave signals φA and φB bythe transmitting circuit 220 so as to be input into the transmittingelectrodes 231 and 232 of the wheel train mechanism 16. The transmittedsine wave signals φA and φB are modulated and synthesized by the signalmodulating means 230 so as to become the received sine wave signal φC.The received sine wave signal φC is received by the receiving electrode235 and is amplified by the receiving circuit 240 so as to become thereceived signal Pc. The phase of the received signal Pc is compared inthe detecting circuit 260 with the phase of the reference signal Pabgenerated in the reference signal generating circuit 250, and themechanical time information held by the wheel train mechanism 16 isdetected from the compared result. The control means 21A controls timesynchronization or time setting based on the mechanical time informationobtained from the detecting circuit 260 and the electric timeinformation held in the counting circuit 13. The control informationfrom an external operating means, not shown, for inputting the timeinformation from the outside is input into the control means 21A, andthe wheel train mechanism 16 is directly and mechanically operated sothat the time can be set.

The transmitting electrodes 231 and 232 and the receiving electrode 235are arranged in a non-contact manner so as to sandwich the rotor 233 ofthe signal modulating means 230. The received sine wave signal φc, whichis obtained by being modulated by capacitive coupling of thetransmitting electrodes 231, 232 and the receiving electrode 235, isinput into the amplifying circuit 241 of the receiving circuit 240.Similarly, the transmitted sine wave signals φA and φB from thetransmitting circuit 220 are input to the capacitors 252 and 253. Thereference sine wave signal φab which is synthesized by capacitivecoupling of the capacitors 252 and 253 is input to the amplifyingcircuit 251 of the reference signal generating circuit 250. Thecapacitors 252 and 253, which are used for capacitive coupling in orderto obtain the reference sine weave signal φab, can be chip capacitors,and it is preferable for reducing cost and space so that they areprovided in one and the same circuit chip.

Since the received sine wave signal φC which is transmitted via the gearis weak due to the size of the gear and a distance between theelectrodes (50 to 100 μm), the capacitors provided in IC may be small.The transmitting circuit 220 and the reference signal generating circuit2 so as well as the capacitors 252 and 253 are arranged on one and thesame circuit chip.

In the position detecting system of the electric watch according to thesecond example of the present invention, as mentioned above, thetransmitted sine wave outputs φA and φB of the BPF amplifying circuitsin the transmitting circuits 220 are transmitted to the transmittingelectrodes 231 and 232 of the signal modulating means 230. The receivedsine wave signal φC from the received electrode 235 is amplified so asto be saturated by the amplifying circuit 241 of the receiving signal240 so that the pulse type received signal Pc is obtained. The referencesine wave signal φab is generated at the capacitor end of the referencesignal generating circuit 250 into which the transmitted sine waveoutputs φA and φB are input. The reference sine wave signal φab isamplified so as to be saturated by the amplifying circuit 251 of thereference signal generating circuit 250, so that the pulse shapereference signal Pab is obtained. The two BPF amplifying circuits 221and 222 of the transmitting circuit 220 have the same circuitconfiguration, and the amplifying circuit 241 of the receiving circuit240 and the amplifying circuit 251 of the reference signal generatingcircuit 250 have the same circuit configuration. The amplitude of thesignals and the amplification factor of the circuits are set so as to beequal with each other.

For this reason, the received signal Pc as the output from the receivingcircuit 240 and the reference signal Pab as the output from thereference signal generating circuit 250 change together even if they areinfluenced by the temperature, and thus the phase relationship does notrelatively change at all. For this reason, Sens-out of the detectedoutput form the detecting circuit 260 can be stable without theinfluence of the temperature.

The BPF amplifying circuits 221 and 222 of the transmitting circuit 220,the capacitors 252 and 253 of the reference signal generating circuit250, and the amplifying circuit 251 are provided in one and the samecircuit chip. As a result, the cost reduces and the space can be small.

In the second example of the present invention, the reference signalgenerating circuit is a circuit which, for example, shapes thetransmitted signals transmitted from the transmitting circuit, andoutputs the reference signal. Further, it may be a circuit in which atleast above-mentioned transmitting circuit and above-mentioned referencesignal generating circuit are formed in one and the same circuit chip,and the capacitors for inputting the transmitted signals into thereference signal generating circuit is provided in the circuit chip.

In this example, the reference signal is obtained in the circuit inwhich the output of the transmitting circuit and the input of thereference signal generating circuit are connected by capacitive couplingusing the capacitor formed in the circuit chip, and input signal of thereference signal generating circuit is shaped.

THIRD EXAMPLE

The position detecting system of the electric watch according to a thirdexample of the present invention is explained below with reference toFIGS. 25 and 27.

That is to say, as the third example of the present invention, theelectric watch, which has the detecting mechanism for detecting theposition information of the rotating member to be measured, includes atransmitting circuit, the transmitting electrode, signal modulatingmeans, the receiving electrode, a receiving circuit, a reference signalgenerating circuit and a detecting circuit. The transmitting circuitgenerates a plurality of transmitted signals. The output signal from thetransmitting circuit is applied to the transmitting electrode. Thereceiving electrode receives a signal from the transmitting electrode.The rotor is provided between the transmitting electrode and thereceiving electrode, and modulates the transmitted signal output fromthe transmitting electrode. The modulated signal received by thereceiving electrode is input to the receiving circuit. The referencesignal generating circuit generates a reference signal for detecting theposition information of the rotor based on the transmitted signalsoutput from the transmitting circuit. The detecting circuit compares theoutput signal from the receiving circuit with the reference signal fromthe reference signal generating circuit so as to detect the mechanicalposition information of the rotor. The electric watch further includes asignal fine adjusting circuit for adjusting at least one of the receivedsignal and the reference signal based on the output from the detectingcircuit, which represents the relationship between the received signalreceived by the receiving circuit and the reference signal shaped by thereference signal generating circuit.

That is to say, the position detecting system according to the thirdexample of the present invention is provided with the signal fineadjusting circuit 254 instead of the capacitor 253 in FIG. 22 in orderto finely adjust the phase of the reference signal Pab. The signal fineadjusting circuit 254 includes a first switch T1, a second switch T2, athird switch T3, and capacitors 255, 256 and 257 with differentcapacities. An output terminal of the BPF amplifying circuit 221 isconnected with one terminals of the first switch T1, the second switchT2 and the third switch T3. The other terminal of the first switch T1 isconnected with one terminal of the capacitor 255, and the other terminalof the second switch T2 is connected with one terminal of the capacitor256. The other terminal of the third switch T3 is connected with oneterminal of the capacitor 257, and the other terminals of the capacitors255, 256 and 257 are connected with an input terminal of the amplifyingcircuit 251. The switches T1, T2 and T3 are composed of transmissiongates (hereinafter, TG), and these switches as well as the capacitorsare formed in an IC circuit chip.

The phase of the transmitted sine wave signal φA is not finely adjusted,but the signal fine adjusting circuit 254 is provided as shown in FIG.25 instead of the capacitor 252 in FIG. 22 so as to be capable of finelycontrolling the phase of the reference signal Pab of the referencesignal generating circuit 250.

The necessity of the fine adjustment will be explained with reference toFIG. 27.

For detecting hand position of the electric watch using the pulse motor,a phase detection is carried out in a state that the movement of thehands is stopped. When, however, the position of the second hand isdetected, for example, the tooth positional relationships between arotor and a rotor pinion, between a fifth wheel and a fifth pinion, andbetween a fourth wheel and a fourth shaft in the pulse motor are notestablished when the parts are assembled. Dispersion occurs in eachwatch, and the phase of the reference signal is close to the phase ofthe detected signal. Since the jolting of the backlash of the gears arealways present, mis-detection is made that the phase of the receivedsignal Pc is close to the phase of the reference signal Pab in thewatches.

FIG. 27 is an explanatory diagram of the reason that the fine adjustmentof the phases of the reference signal and the detected signal isnecessary. The phase angles of the detected signal and the referencesignal are plotted along a vertical axis, and the rotating position ofthe detecting wheel 43 (FIG. 6) is plotted along a horizontal axis. Eachplot represents a stop position of the detecting wheel 43. As therotation of the detecting wheel 43 proceeds, the received signal changesfrom −45° to +45°. For example in FIG. 27, in the case of a pattern 1,since the stop angles corresponding to white circle shift from the phaseangle of the reference signal, the phase of the received signal isseparated from the phase of the reference signal, and thus,mis-detection is not made. Similarly, in the case of a pattern 2, sincethe stop angles corresponding to black triangles shift from the phaseangle of the reference signal, mis-detection is not made. In the case ofa pattern 3, since some of the stop angles corresponding to blacksquares are close to the phase angle of the reference signal, the phaseof the received signal is close to the phase of the reference pulsesignal, and mis-detection is made.

In the case of the pattern 3, therefore, one of the transmitted sinewave signals φA and φB in FIG. 25 are modulated by a capacity valuewhich is adjusted in capacitance which is obtained in a manner that thetransmission gates T1, T2 and T3 are controlled so as to switch thecapacitors 255, 256 and 257 of the signal fine adjusting circuit 254.The shift of a first reference signal Pab as the initial setting in thereference signal generating circuit 250 is shifted to the delay oradvance direction so as to be a second reference signal Pab. As aresult, like the pattern 1 or 2, the phases of the received signal andthe reference signal are separated from each other, thereby preventingmis-detection.

It is desirable that the signal fine adjusting circuit of this exampleis configured so as to finely adjust either one of the phase of thereceived signal and the phase of the reference signal. Further, it isdesirable that the signal fine adjusting circuit has a plurality ofcapacitors, and the capacitance value of the circuit is adjustable.

Further, in this example, it is preferable that the signal fineadjusting circuit has an amplitude adjusting circuit, and the amplitudeadjusting circuit adjusts the amplitude of the transmitted signal on apath between the transmitting circuit and the transmitting electrode orbetween the transmitting circuit and the reference signal generatingcircuit.

On the other hand, in this example, as explained above, it is preferablethat the signal fine adjusting circuit creates two-level states betweenthe received signal and the reference signal, and selects a stable statebased on the detected results of the states at plural times by means ofthe detecting circuit. Further, it is preferable that the signal fineadjusting circuit creates three-level states between the received signaland the reference signal, and selects a suitable state based on thedetected result of the states by means of the detecting circuit.

FOURTH EXAMPLE

The position detecting system of the electric watch according to afourth example of the present invention is explained below withreference to FIG. 26.

In the fourth example, the signal fine adjusting circuit 242 is providedin the input of the receiving circuit 240 in FIG. 22 of the secondexample. In the case of the pattern 3 in FIG. 27, instead of the phaseof the reference signal Pab from the reference signal generating circuit250 being shifted, the phase of the received signal Pc from thereceiving circuit 240 is shifted.

The signal fine adjusting circuit 242 in FIG. 26 has the same circuitconfiguration as that of the signal fine adjusting circuit 254 in FIG.25. The signal fine adjusting circuit 242 includes a fourth switch T4, afifth switch T5, a sixth switch T6, and the capacitors 243, 244 and 245with different capacities. An output terminal of the BPF amplifyingcircuit 222 is connected with one terminals of the fourth, the fifth andthe sixth switches T4, T5 and T6, and the other terminal of the fourthswitch T4 is connected with one terminal of the capacitor 243. The otherterminal of the fifth switch T5 is connected with one terminal of thecapacitor 244, and the other terminal of the sixth switch T6 isconnected with one terminal of the capacitor 245. The other terminals ofthe capacitors 243, 244 and 245 are connected with an input terminal ofthe amplifying circuit 241 of the receiving circuit 240. The otherconnection is similar to that in FIG. 22. The control means 21A controlsswitching of the switches T4 to T6, so that the phase of the firstreceived signal Pc as the initial setting is shifted to the delay oradvance direction so as to be switched into the second received signalPc. The phases of received signal and the reference signal are separatedfrom each other, thereby preventing mis-detection. Instead that thedetected signal φC is synthesized with the transmitted signal φB, thedetected signal φC may be synthesized with the transmitted signal φA.

In the third and the fourth examples of the present invention, the firstreference signal Pab as the initial setting is switched into the secondreference signal Pab obtained by adjusting the phase using the signalfine adjusting circuit. In another manner, the first detected signal Pcas the initial setting is switched into the second detected signal Pcobtained by adjusting the phase using the signal fine adjusting circuit.As a result, the position can be detected even if each watch hasdispersion.

FIFTH EXAMPLE

The position detecting system of the electric watch according to a fifthexample of the present invention is explained below with reference toFIGS. 28 to 31.

In the position detecting system of the fifth example, three referencesignals are used, and the detecting accuracy is heightened. Since thecircuit configuration is the approximately same as that of the positiondetecting system in the third example, it is explained with reference toFIGS. 24, 25, 28, 29, 30 and 31.

The control means 21A in FIG. 24 controls the switches T1, T2 and T3 ofthe signal fine adjusting circuit 254 in FIG. 25 according to aflowchart of a reference signal setting program software in FIG. 31, andthe reference signal generating circuit 250 generates three referencepulse signals with different phases. The three pulse reference signalswith different phases are a reference signal A, a reference signal B anda reference signal C.

As shown in FIG. 28, the setting of the reference signal, when the handmoving step of the hand position detection comes to a position slightlydelayed from the phase angle 0°, is explained below.

In FIG. 28, the hand moving step is stopped in positions represented bywhite circles, and enters a range represented by an arrow. In FIG. 31,the initial setting is executed so that the reference signal A istemporarily set at step 1 (hereinafter, S1), the hand is moved by onestep at S2, and detection is made at S3. When the detected result is theL level in FIG. 13 (hereinafter, “−”), the sequence returns to S2, andthe hand is again moved by one step, and the detection is made at S3.When the detected result is the H level in FIG. 13 (hereinafter, “+”),the reference signal B is temporarily determined at S4, and detection ismade at S5. Since the result is “−”, the reference signal C isdetermined at S6. As a result, the reference signal C with large phaseangle is used, and thus the reference signal can be set in anapproximately intermediate position between the stop position of thegear and the next stop position with avoiding the reference signal A orB close to the stop position.

As shown in FIG. 29, the state that the hand moving step comes to aposition slightly advancing with respect to the phase angle 0° isexplained.

In FIG. 29, the hand moving step stops in positions represented by blacksquares, and enters a range represented by an arrow. In FIG. 31, theinitial setting is executed so that the reference signal A istemporarily set at S1, and the hand is moved in a stepped manner at S2,and the detection is made at S3. When the result is “−”, the sequencereturns to S2, and the hand is moved again by one step, and thedetection is made at S3. When the result is “+”, the reference signal Bis temporarily set at S4, and detection is made at S5. Since the resultis “+”, the reference signal C is temporarily set at S7, and detectionis made at S8. Since the result is the reference signal A is determinedat S9. As a result, the reference signal A with small phase angle isused, so that the reference signal B or C which is close to the stopposition is avoided, and the reference signal can be set in anapproximately intermediate position between the stop position of thewheel and the next stop position.

Further, as shown in FIG. 30, the state that the hand moving step comesto a position separated from the phase angle of 0° is explained.

In FIG. 30, the hand moving step stops in positions represented by blacktriangles, and enters a range represented by an arrow. In FIG. 31, theinitial setting is executed so that the reference signal A istemporarily set at S1, and the hand is moved by one step at S2, anddetection is made at S3. When the result is “−”, the sequence returns toS2 so that the hand is again moved by one step, and detection is made atS3. When the result is “+”, the reference signal B is temporarilydetermined at S4, and detection is made at S5. Since the result is “+”,the reference signal C is temporarily set at S7, and detection is madeat S8. When the result is “+”, the reference signal B is determined atS10. As a result, the reference signal B which is close to the phaseangle of 0° is used, so that the reference signal A or C which is closeto the stop position is avoided, and the reference signal can be set inan approximately intermediate position between the stop position of thegear and the next step position.

When the three reference signals with different phases are switched, thereference signal can be set at the approximately intermediate phase ofthe Stop positions of the gear. For this reason, even if there arebacklashes or dispersions of the tooth positional relationships betweenthe rotor and the rotor pinion of the pulse motor which rotates 180° inone step, between the fifth wheel and the fifth pinion and between thefourth wheel and the fourth shaft at the time of assembly of parts ineach watch or backlash in each gear, the position can be detectedaccurately. Although the two or three reference signals are switched inthe above example, when more than three reference signals are used, morefine measurement can be made. When the phase is changed from minus toplus, the phase of the reference signal can be set just in the middlebetween the stop state of the gear and the next stop state. When achange amount of the phase at one pitch of the gear is extremely small,this case is particularly effective.

SIXTH EXAMPLE

The position detecting system of the electric watch according to a sixthexample of the present invention is explained below with reference toFIGS. 32 to 34.

The position detecting system of the sixth example has a signal fineadjusting circuit 258 having an amplitude adjusting circuit 259 which isprovided on either one of the signal paths between the output terminalof the transmitting circuit 220 and the transmitting electrodes 231 and232 (FIG. 32) or as shown in FIG. 34, on either one of the signal pathsbetween the output terminal of the transmitting circuit 220 and thecapacitors 252 and 253 of the reference signal generating circuit 250.

As shown in FIG. 32, the signal fine adjusting circuit 258 including theamplitude adjusting circuit 259 is provided between the BPF amplifyingcircuit 221 of the transmitting circuit 220 and the transmittingelectrode 231, and the amplitude of the transmitted sine wave signal φAis set to be large by the amplitude adjusting circuit 258 as shown inFIG. 33. In this case, the phase of the received sine wave signal φC isclose to the phase of φA. In such a manner, the amplitude of thetransmitted sine wave signal which is one input of the signal modulatingmeans 230 is finely adjusted, so that the phase of the received signalPc from the receiving circuit 240 can be finely adjusted.

Similarly as shown in FIG. 34, the signal fine adjusting circuit 258having the amplitude adjusting circuit 259 is provided between thetransmitting circuit 220 and one capacitor of the reference signalgenerating circuit 250 so as to finely adjust the amplitude of thetransmitted sine wave signal φA or φB. As a result, the phase of thereference signal Pab can be finely adjusted.

As is clear from the above explanation, in the respective examples ofthe present invention, the received sine wave signal φC from thereceiving electrode 235 in the signal modulating means 230 receiving thetransmitted sine wave signal φA or φB of the BPF amplifying circuit inthe transmitting circuit 220 is amplified so as to be saturated by theamplifying circuit 241 of the receiving circuit 240 so that the receivedsignal Pc is obtained. The transmitted sine wave signal C is amplifiedso as to be saturated by the amplifying circuit 251 of the referencesignal generating circuit 250 inputting the transmitted sine wave signalφA or φB, so that the reference signal Pab is obtained. Further, the twoBPF amplifying circuits 221 and 222 of the transmitting circuit 220 havethe same circuit configuration, and the receiving circuit 240 whoseoutput is the received signal Pc and the amplifying circuit 251 of thereference signal generating circuit 250 have the same circuitconfiguration. The amplitude of the signals and the amplificationfactors of the circuits are set to be equal with each other.

As described above, in the second to sixth examples, the received signalPc which is the output from the receiving circuit 240 and the referencesignal Pab which is the output from the reference signal generatingcircuit 250 change together even if they are influenced by temperature,accordingly, the relative phase relationship between the received signalPc and the reference signal Pab does not change at all. For this reason,Sens-out as the detected output from the detecting circuit 260 becomes astable output which is not influenced by temperature.

In the above examples of the present invention, the BPF amplifyingcircuits 221 and 222 of the transmitting circuit 220, the capacitors 252and 253 of the reference signal generating circuit 250, and theamplifying circuit 251 are formed in one and the same circuit chip. As aresult, the cost is reduced, and the space can be small.

Further, the two or three reference signals with different phases areswitched according to the stop positions of the hand moving step, sothat the position can be detected by the reference signal with optimalphase. As a result, even if there are dispersions of the toothpositional relationships between the rotor and the rotor pinion of thepulse motor, between the fifth wheel and the fifth pinion, and betweenthe fourth wheel and the fourth shaft at the assembly of the parts ineach watch or the backlash in each gear, the position can be detectedsecurely.

Not only the second position detection but also the mechanical positiondetections of the day plate, the week plate and the like of the watchcan be made, so that the position detecting system of the electric watchwith non-contact, low electric power, small space, low cost and highreliability can be realized.

As a result, a wrist watch with high reliability of holding time, aradio wave correcting wrist watch with a time early correcting function,a wrist watch with a month-end automatic correcting function, a wristwatch with large hands and good design properties, and the like can beput into a practical use.

SEVENTH AND EIGHTH EXAMPLES

The position detecting system of the electric watch according to seventhand eighth examples of the present invention is explained below withreference to FIGS. 35 to 38.

The basic technical constitution of the seventh and eighth examples ofthe present invention is the electric watch having the detectingmechanism for detecting the position information of the rotating memberto be measured. The electric watch includes a transmitting circuit, thetransmitting electrode, signal modulating means, the receivingelectrode, a receiving circuit. The transmitting circuit generates aplurality of transmitted signals. The output signal from thetransmitting circuit is applied to the transmitting electrode. Thereceiving electrode receives a signal from the transmitting electrode.The rotor is provided between the transmitting electrode and thereceiving electrode, and modulates the transmitted signal output fromthe transmitting electrode. The modulated signal received by thereceiving electrode is input to the receiving circuit and is amplifiedby the receiving circuit. The reference position of the rotor isdetected based on the phase change of the received signal. The pluraltransmitting electrodes and the receiving electrode are arranged so asto be opposed to each other along the approximately entire rotatingsurface of the rotor.

In the seventh and eighth examples, since the circuit configuration inFIG. 22 is used as the electric constitution, the waveforms of therespective portions are as shown in FIG. 11.

FIG. 35 illustrates the wheel train mechanism including signalmodulating means in the position detecting system according to theseventh and eighth examples.

As shown in FIG. 35, the rotating shafts of the respective wheel trainsare mounted to a ground plate 325 and a wheel train receiver 326rotatively. The numeral 328 designates the rotor of the pulse motor, thenumeral 329 designates a stator, and the numeral 327 designates thefifth wheel for decelerating and transmitting the rotation of the rotor328 of the pulse motor. The fifth wheel 327 transmits the rotation of areduction ratio to the fourth wheel, not shown, and transmits therotation of the same reduction ratio to the detecting wheel 336 which isthe rotor 233 composing the signal modulating means 230 (FIG. 22). Thesecond hand is fixed to the fourth wheel, and second information isdisplayed thereon. The fourth wheel and the detecting wheel 336 move thehand synchronously in the stepped manner by one rotation at 60 steps,namely, 6° per step.

The detecting wheel 336 is composed of a metal member havingelectrically conductivity, and electrically conductive bearings such asmetal bushes are used as upper and lower bearings of the detecting wheel336. The detecting wheel 336 is grounded to a high potential side or alow potential side of a power supply line via the wheel train receiveror the ground plate (not shown). This example uses the bearings, butneedless to say, the upper and lower bearings may be integral with thewheel train receiver or the ground plate. The rotating surface of thedetecting wheel 336 has a detecting hole 334. Electric conductivity orpermittivity of the detecting wheel 336 in the rotating direction aredifferent from those of the other portion due to the detecting hole 334.The transmitting electrode is formed on a circuit board 1 (323) belowthe rotating surface of the detecting wheel 336, and the receivingelectrode is formed on a circuit board 2 (324) above the rotatingsurface.

The signal modulating means of the seventh example is explained withreference to FIG. 36. FIG. 36( a) is a plan view of the receivingelectrode 335, and the receiving electrode 335 is formed on the circuitboard 2 (324) opposed to the rotating surface of the detecting wheel336. FIG. 36( b) is a plan view of the detecting wheel 336 as the rotor,and the detecting hole 334 is provided on the rotating surface. FIG. 36(c) is a plan view of the transmitting electrode in the seventh example.The transmitting electrodes 331 and 332 are arranged on the circuitboard 1 (323) so as to occupy same area for 180° and be opposed to therotating surface of the detecting wheel 336.

FIG. 36( d) is a plan view of the transmitting electrodes of the eighthexample. The area of one transmitting electrode 331 is small, and thearea of the other transmitting electrode 332 is large, so that the phaseangle changes only by a portion of one rotation of the detecting wheel336.

The phase change of the received signal from the receiving electrode inthe seventh example when the transmitting electrodes in FIG. 36( c) areused is explained with reference to FIG. 37. The transmitted signals φAand φB transmitted from the transmitting electrodes 331 and 332 in FIG.36( c) are received by the receiving electrode 335 in FIG. 36( a), butthe phase change of the received signal Pc due to the rotation of thedetecting wheel 336 is shown in FIG. 37. The phase angles of thereceived signal Pc and the reference signal Pab are plotted along avertical axis, and the rotating position of the detecting wheel 336 isplotted along a horizontal axis. The plotted points represent the stoppositions of the detecting wheel 336.

In FIG. 37, the detecting hole 334 of the detecting wheel 336 is on thetransmitting electrode 332, and the phase angle is −45°. As thedetecting hole 334, however, overlaps with a portion of the transmittingelectrode 331, the phase angle advances due to the rotation of thedetecting wheel 336. When the center of the detecting hole 334 comes toa boundary between the transmitting electrodes 331 and 332, the phaseangle becomes 0°. Further, when detecting wheel 336 rotates and thedetecting hole 334 comes onto the transmitting electrode 331, the phaseangle becomes +45°. As the detecting wheel 336 further rotates and thedetecting hole 334 overlaps a portion of the transmitting electrode 332,the phase angle delays. When the center of the detecting hole comes ontothe boundary between the transmitting electrodes 331 and 332, the phaseangle becomes 0°. When the detecting wheel 336 further rotates so as tobe on the transmitting electrode 332, the phase angle is again in theinitial state, namely, −45°. The explanatory diagram of the phase changeof the received signal shown in FIG. 37 illustrates an ideal phasechange for easy understanding of the explanation. Even when thedetecting hole 334 is on one transmitting electrode, the transmittedsignal from the other transmitting electrode is slightly transmitted tothe receiving electrode 335. For this reason, an actual phase changeamount reduces as compared with the line in FIG. 37. In an explanatorydiagram of another phase change, mentioned later, the ideal phase changeis shown similarly to FIG. 37 in order to clarify the explanation.

The transmitting electrodes 331 and 332 are arranged in a divided mannerby 180° so as to opposed to the approximately entire periphery of therotating surface of the detecting wheel 336. The receiving electrode 335is formed along the entire periphery of the rotating surface of thedetecting wheel 336, so that the phase angle can be detected even if thedetecting wheel 336 is in any positions. For this reason, when thetransmitting electrodes and the receiving electrode are arranged on aportion opposed to the detecting wheel 336, presence or non-presence ofsignals is checked according to the electric field intensity of thereceived signal, and the position should be detected by the phase angleof the received signal. When, however, the transmitting electrodes andthe receiving electrode are arranged on the approximately entireperiphery of the detecting wheel 336, the position of the detectingwheel 336 can be detected only by detecting the phase angle of thereceived signal. For this reason, the circuit configuration can begreatly simplified, and the detecting accuracy can be improved.According to this configuration, since the phase changes twice a tonerotation, the position can be detected twice a tone rotation, so thatthe detecting accuracy is improved.

As an eighth example of the present invention, the phase change of thereceived signal from the receiving electrode when the secondtransmitting electrodes in FIG. 36( d) are used in the signal modulatingmeans is explained below with reference to FIG. 38.

The transmitted signals φA and φB transmitted from the transmittingelectrodes 331 and 332 in FIG. 36( d) are received by the receivingelectrode 335 in FIG. 36( a), but the phase change of the receivedsignal Pc due to the rotation of the detecting wheel 336 is similarly asshown in FIG. 38. In the phase change, the angle of +45° decreases ascompared with the seventh example, and the phase change is mostly −45°.Since the other parts of the change is completely similar to the exampleusing the first transmitting electrode in FIG. 36( c), the detailedexplanation thereof is omitted.

That is to say, since the sizes of the two transmitting electrodes canbe set freely, they can be set at a suitable ratio according to thefactor of the circuit configuration and the factor of the arrangement ofthe receiving electrode.

The configuration is such that the transmitting electrode 331 which issmall and the transmitting electrode 332 which is large are arranged soas to opposed to the approximately entire periphery of the rotatingsurface of the detecting wheel 336 and a part of the phase is changed.The receiving electrode 335 is formed along the entire periphery of therotating surface of the detecting wheel 336, so that the phase angle canbe detected even if the detecting wheel 336 is in any positions ascompared with the case where the transmitting electrodes and thereceiving electrode are arranged opposed to the detecting wheel on oneportion. Further, since the phase is changed twice every one rotation,the circuit configuration can be simplified and the detecting accuracyis improved.

NINTH EXAMPLE

The position detecting system of the electric watch according to a ninthexample of the present invention is explained below with reference toFIGS. 39 and 40.

FIG. 39( a) is a plan view of the receiving electrode. Similarly to thereceiving electrode in FIG. 36( a), the receiving electrode 335 isformed on the circuit board 2 (324) opposed to the rotating surface ofthe detecting wheel 336. FIG. 39( b) is a plan view of the detectingwheel 336 which is the rotor 233 (FIG. 22). The rotating surface of thedetecting wheel 336 has a plurality of detecting holes 342, 243, 344,345 and 346, in which each angle formed between a pair of two adjacentlyarranged holes to each other with respect to a rotating axis of therotor is different from that formed between a separate pair of twoadjacently arranged holes to each other with respect to the rotatingaxis. FIG. 39( c) is a plan view of the transmitting electrodes. Aplurality of transmitting electrodes 354, 355, 356, 357 and 358 fortransmitting one of the two transmitted signals, and a plurality oftransmitting electrodes 364, 365, 366, 367 and 368 for transmitting theother transmitted signal are arranged alternatively on the circuit board1 (323) so that their number is the same as that of the detecting holes.The transmitting electrodes are formed into a cord shape so that allboundary portions of the transmitting electrodes match the detectingholes of the detecting wheel 336 only once, respectively, at onerotation of the detecting wheel 336. The transmitting electrodes 354,355, 356, 357 and 358 are connected by a pattern on the rear side of theboard, and the transmitting electrodes 364, 365, 366, 367 and 368 areconnected by a pattern on the surface side.

The phase change of the received signal from the receiving electrodewhen the signal modulating means of the ninth example is used isexplained with reference to FIG. 40. The transmitted signal φBtransmitted from the transmitting electrodes 354, 355! 356, 357 and 358in FIG. 39( c) and the transmitted signals φA transmitted from thetransmitting electrodes 364, 365, 366, 367 and 368 are received by thereceiving electrode 335 in FIG. 39( a). The phase change of the receivedsignal Pc due to the rotation of the detecting wheel 336, however, is asshown in FIG. 40. The phase angles of the received signal Pc and thereference signal Pab are plotted along a vertical axis of FIG. 40, andthe rotating position of the detecting wheel 336 is plotted along ahorizontal axis. Plotted points represent the stop positions of thedetecting wheel.

In FIG. 40, all the detecting holes 342, 343, 344, 345 and 346 of thedetecting wheel 336 are on any of the transmitting electrodes 364, 365,366, 367 and 368, and the phase angle is +45°. When any one of thedetecting holes 342, 343, 344, 345 and 346, however, comes onto thetransmitting electrode 354, 355, 356, 357 or 358 due to the rotation ofthe detecting wheel 336, the phase angle changes slightly to the delaydirection. When the detecting wheel 336 further rotates, all thedetecting holes 342, 343, 344, 345 and 346 are again on any of thetransmitting electrodes 364, 365, 366, 367 and 368, and the phase angleis +45°. This state is repeated hereinafter, but all the detecting holes342, 343, 344, 345 and 346 come onto the transmitting electrodes 354,355, 356, 357 and 358 only once every rotation of the detecting wheel336. Only at this time, the phase angle is −45°.

That is to say, when the detecting holes 342, 343, 344, 345 and 346 comeonto boundaries between the transmitting electrodes 364, 365, 366, 367and 368 and the transmitting electrodes 354, 355, 356, 357 and 358, thephase of the received signal is changed from the plus into the minusstate. For this reason, this timing can be detected as the referenceposition.

The five detecting holes 342, 343, 344, 345 and 346 are provided on therotating surface of the detecting wheel 336 so as to form differentangles with the rotating axis being the center. The five transmittingelectrodes 354, 355, 356, 357 and 358 for transmitting the transmittedsignal φB and the five transmitting electrodes 364, 365, 366, 367 and368 for transmitting the transmitted signal φA are arrangedalternatively. The transmitting electrodes are formed into the cordshape so that all the detecting holes match all the boundary portions ofthe transmitting electrodes only once at per rotation of the detectingwheel 336, so that the phase is detected in five places. As a result,the phase change amount of the received signal at one step is largerthan that of the detection in one place, so that the detecting abilitybecomes high and the detection can be made accurately.

TENTH EXAMPLE

The position detecting system of the electric watch according to a tenthexample of the present invention is explained below with reference toFIGS. 41 and 42.

FIG. 41( a) is a plan view of the transmitting electrodes. Thetransmitting electrodes 331 and 332 are formed on the circuit board 1(323), and an electrode shape of the boundary portion between thetransmitting electrodes 331 and 332 is constituted so as to have asmaller area than the other portion. FIG. 41( b) is an explanatorydiagram illustrating an area change of the transmitting electrodesopposed to the detecting hole due to the rotation of the detecting wheelwhen the transmitting electrodes in the signal modulating means of theseventh example are used. FIG. 41( c) is an explanatory diagramillustrating an area change of the transmitting electrodes opposed tothe detecting hole due to the rotation of the detecting wheel when thetransmitting electrodes of the signal modulating means in the tenthexample are used. FIG. 42 is an explanatory diagram for comparing thephase change of the received signal from the receiving electrode whenthe transmitting electrodes in the signal modulating means of the tenthexample are used with the phase change when the transmitting electrodesin the signal modulating means of the seventh example are used.

As to the transmitted electrodes in the signal modulating means of theseventh example, as shown in FIG. 41( b), the electrode shape of theboundary portion between the transmitting electrodes 331 and 332 is thesame as the electrode shape of the other portion. For this reason, thephase angle of the received signal from the receiving electrode changesso that a comparatively straight line is drawn from −45° and gentlyrises to reach +45° as shown by white circles in FIG. 41 according tothe movement of the stop positions t1, t2, t3, t4, t5 and t6(corresponding to the second hand positions) due to the rotation of thedetecting wheel.

On the contrary, as to the transmitting electrodes in the signalmodulating means of the tenth example, as shown in FIG. 41( c), theelectrode area of the boundary portion between the transmittingelectrodes 331 and 332 is set so as to be smaller than the electrodearea of the other portion. For this reason, when the detecting hole 334passes through the boundary between the transmitting electrodes 331 and332, namely, when the phase of the received signal for detecting theposition passes through 0° according to the movement of the stoppositions t1, t2, t3, t4, t5 and t6 due to the rotation of the detectingwheel as shown by black circles in FIG. 42, the phase angle of thereceived signal from the receiving electrode changes greatly. As aresult, the position detecting ability can be improved.

ELEVENTH EXAMPLE

The position detecting system of the electric watch according to aneleventh example of the present invention is explained below withreference to FIGS. 43 and 44.

FIG. 43 is a plan view of the transmitting electrodes. The transmittingelectrodes 331 and 332 are arranged on the circuit board 1 (323) so thattwo electrode shapes of the boundary portions therebetween are differentfrom each other. FIG. 44 is an explanatory diagram of the phase changeof the received signal from the receiving electrode when thetransmitting electrodes in the signal modulating means of the eleventhexample are used.

In FIG. 44, the detecting hole 334 of the detecting wheel is on thetransmitting electrode 332 at first, and the phase angle of the receivedsignal from the receiving electrode is −45°. When, however, thedetecting wheel rotates and the detecting hole 334 comes to the firstboundary portion, the phase angle becomes 0°, and when the detectingwheel further rotates and the detecting hole 334 comes onto thetransmitted electrode 331, the phase angle becomes +45°. Further, whenthe detecting wheel rotates, the detecting hole 334 again comes from thetransmitting electrode 331 onto the detecting electrode 332 via thesecond boundary portion between the transmitting electrodes. Since,however, the electrode shape of the second boundary portion is differentfrom the electrode shape of the first boundary portion, a gradient ofthe phase change in the second boundary portion is more gentle than thatof the first boundary portion. When two signals of the references 1 and2 shown in FIG. 44 are prepared and they are used as the referencesignals of the detecting circuit 60, a detection can be made whichgradient is for the phase change. In addition to the mechanical positioninformation, the rotating direction can be detected according to achange in the phase and the gradient of the received signal from thereceiving electrode due to the rotation of the detecting wheel. That isto say, a number of the stop positions in an intermediate phase changingfrom a state that the phase of the received signal delays with respectto that of the reference 1 signal into a state that the phase of thereceived signal advances with respect to that of the reference 2 signalis counted. In FIG. 44, the rotating direction can be detected in such amanner that when the number of the stop positions is two, the rotatingdirection is a regular direction, and when the number is four, therotating direction is a reverse direction.

TWELFTH EXAMPLE

The position detecting system of the electric watch according to atwelfth example of the present invention is explained below withreference to FIGS. 45 and 46.

FIG. 45( a) is a plan view of the transmitting electrodes. Thetransmitting electrode 335 is formed on the circuit board 2 (324). FIG.45( b) is a plan view of the detecting wheel, and the rotating portionof the detecting wheel 336 has the detecting hole 334. FIG. 45( c) is aplan view of the transmitting electrodes. The transmitting electrodes374, 375 and 376 for transmitting one of the two transmitted signals andthe transmitting electrodes 384, 385 and 386 for transmitting the othertransmitted signal are formed alternatively on the circuit board 1(323). The transmitting electrodes 374, 375 and 376 are connected by apattern on the circuit board 1 (323), and the transmitting electrodes384, 385 and 386 are connected by a pattern on a rear side of thecircuit board 1 (323). The electrode constitution is such that thetransmitting electrodes change at different angles in at least threeplaces with the rotating shaft of the detecting wheel 336 being acenter.

FIG. 46 is an explanatory diagram illustrating the phase change of thereceived signal from the receiving electrode when the signal modulatingmeans of the twelfth example is used.

Since the transmitting electrodes have the shape such that they arechanged at different angles, the phase change according to the rotationof the detecting wheel 336 is as shown in FIG. 46. Since the anglesbetween the boundary portions formed between the transmitting electrodesare T1, T2 and T3, namely, are different from each other, the angle T1,T2 and T3 is detected in order in the regular rotation, and the angleT1, T3 and T2 is detected in order in the reverse rotation. In such amanner, since the change patterns are different, by detecting the abovementioned order, the rotating direction as well as the mechanicalposition information can be detected.

THIRTEENTH EXAMPLE

The position detecting system of the electric watch according to athirteenth example of the present invention is explained below withreference to FIGS. 47 and 48.

FIG. 47 is a plan view of the transmitting electrodes. The transmittingelectrode 331 having a large area for transmitting the transmittedsignal with phase of +90°, the transmitting electrode 332 having largearea for transmitting the transmitted signal with phase of −90°, and thetransmitting electrodes 361 and 362 having small area for transmittingthe transmitted signal with phase of 0° are formed on the circuit board1 (323). The transmitting electrode 361 and the transmitting electrode362 are connected by a pattern on the rear side of the circuit board 1(323).

FIG. 48 is an explanatory diagram illustrating the phase change of thereceived signal from the receiving electrode when the signal modulatingmeans of the thirteenth example is used. The detecting hole of thedetecting wheel is on the transmitting electrode 332 at first, and thephase angle of the received signal from the receiving electrode is −90°.When the detecting wheel rotates and the detecting hole is overlappedwith a part of the transmitting electrode 362, the phase angle starts toincrease. When the detecting hole is on the transmitted electrode 362,the phase angle of the received signal from the receiving electrodebecomes 0°. When the detecting wheel further rotates and the detectinghole is on the transmitting electrode 331, the phase angle of thereceived signal from the receiving electrode becomes +90°. When thedetecting wheel further rotates and the detecting hole is overlappedwith a part of the transmitting electrode 361, the phase angle starts todecrease. The detecting hole is on the transmitting electrode 361, thephase angle of the received signal becomes 0°. When the detecting wheelfurther rotates and the detecting hole is again on the transmittingelectrode 332, the phase angle of the received signal from the receivingelectrode becomes −90°.

When the phase difference between the two signals is designated by π,the amplitude of the received signal becomes zero so as not to bedetected. When, however, the two transmitted signals with phasedifference of π, and the one transmitted signal with a just middle phasebetween the phases of the two transmitted signals are used, the phasechange of the received signal can be theoretically enlarged to π by onerotation of the detecting wheel as the rotor.

In the constitution where the moment when the phase of the receivedsignal is changed from the plus state to the minus state is detected asthe reference position, it is not necessary to enlarge the width of thephase change of the received signal in the ideal structure. Actuallyeven when the detecting hole is on one transmitting electrode, however,the signal from the adjacent transmitting electrode is slightlyreceived. For this reason, it is effective to enlarge the entire widthof the phase change of the received signal.

As shown in FIG. 48, since the phase change between one step becomessmall around the phase angle of 0°, in the thirteenth example, the phaseof the reference signal may be shifted slightly from 0° to the plus orminus direction.

In the position detecting system of the electric watch according to theseventh example of the present invention, as shown in the sectional viewof FIG. 35, the circuit pattern for transmitting electrode is formed onthe circuit board 1 (323) as a printed-circuit board provided below thedetecting hole 334 of the detecting wheel 336 as the signal modulatingmeans, and the circuit pattern for the transmitting electrode is formedon the circuit board 2 (324) provided above the detecting hole 334.

The transmitting electrodes and the receiving electrode in the signalmodulating means of the seventh and the thirteenth examples can beformed easily as the circuit pattern on the printed-circuit board.

The printed-circuit board is more realistic and practical than a metalplate or the like.

The board may be a glass epoxy board or an FPC board.

In this example, the transmitting electrodes and the receiving electrodeare formed on the printed-circuit boards, but either one of thetransmitting electrodes and the receiving electrode may formed on theprinted-circuit board.

FOURTEENTH EXAMPLE

The position detecting system of the electric watch according to anfourteenth example of the present invention is explained below withreference to FIG. 49.

FIG. 49 is a diagram illustrating a sectional constitution of theposition detecting system of the electric watch according to the presentinvention. Only the constitution around the circumference of thereceiving electrode is different from the seventh example, and since theother portion is the same, only corresponding portion is explained.

The transmitting electrode below the detecting hole 334 of the detectingwheel 336 is formed on the circuit board 1 (323) as the printed-wiringboard, and the receiving electrode above the detecting hole 334 isformed on the circuit board 2 (324). An integrating circuit (IC) 363having the receiving circuit is mounted on the circuit board 2 (324).

The IC 363 is mounted on the circuit board 2 (324) forming the receivingelectrode thereon so that a circuit block is formed, and thus thereceiving electrode and the receiving circuit can be connected by theshortest length. For this reason, a very small received signal isprevented from being influenced by an external noise or by itstransmitted signal, thereby preventing deterioration of the detectingability.

Further, as shown in FIG. 50, the receiving electrode, is constituted sothat received signal pattern electrically connects a receiving electrodepattern 364 formed on the circuit board 2 (324) as the printed-wiringboard and the integrated circuit (IC) 363 having the receiving circuit.A pattern on the lower surface of the received signal pattern isshielded by a shield pattern 365 as a ground electrode, and a pattern onan upper surface is shielded by a shield pattern 366 as a groundelectrode. These shield patterns include the patterns on the upper andlower surfaces, but needless to say, any one of them may be provided.

The upper and lower surfaces of the received signal pattern forelectrically connecting the receiving electrode and the integratedcircuit having the receiving circuit are shielded, so that the receivingelectrode is hardly influenced by the external noise and the transmittedsignal. As a result, the deterioration of the detecting ability can beprevented. It is effective to shield only one side surface of thedouble-sided board, but it is the most effective to allow the receivedsignal to transmit through a laminated board, and both the upper andlower surfaces of the received signal pattern is shielded.

Further, a sectional constitution of the position detecting system ofthe electric watch according to the present invention is explained withreference to FIG. 51.

In this example, the transmitting electrode below the detecting hole 334of the detecting wheel 336 is formed on the circuit board 1 (323) as theprinted-wiring board, and the receiving electrode 335 above thedetecting hole 334 is constituted so that a conductive film is formed onthe surface of the wheel train receiver 326 as a supporting member ofthe electric watch. Needless to say, the transmitting electrode may beconstituted so that a conductive film is formed on the surface ofanother supporting member such as a ground plate 325.

Instead that the electrodes are formed on the circuit board, the groundplate 325 and the wheel train receiver 326 are made of plastic, and theelectrodes can be formed thereon by plating and coating. The circuitboard is not required, thereby enabling thinning and reduction in thecost.

As is understood from the above examples of the present invention, onecharacteristic of the technical constitutions according to the seventhto the fourteenth examples is that the transmitting electrodes and thereceiving electrode are arranged so as to be opposed to theapproximately entire periphery of the rotating surface of the rotor.

Further, the rotating surface of the rotor in the signal modulatingmeans of the present invention has on its rotating surface a pluralityof detecting holes, in which each angle formed between a pair of twoadjacently arranged holes to each other with respect to a rotating axisof the rotor is different from that formed between a separate pair oftwo adjacently arranged holes to each other with respect to the rotatingaxis. The transmitting electrodes transmit two kinds of the transmittedsignals. The one transmitting electrode for transmitting one transmittedsignal and the other transmitting electrode for transmitting the othertransmitted signal are arranged alternatively so that their number isthe same as that of the detecting holes. It is preferable that theboundary portions of the transmitting electrodes coincide with all thedetecting holes of the rotor only once per rotation of the rotor.

Further, in this example of the present invention, the followingconstitution is preferable. The rotor has on its rotating surface aplurality of detecting holes, in which each angle formed between a pairof two adjacently arranged holes to each other with respect to arotating axis of the rotor is different from that formed between aseparate pair of two adjacently arranged holes to each other withrespect to the rotating axis. A first transmitting electrode outputs afirst transmitted signal, and a second transmitting electrode outputs asecond transmitted signal different from the first transmitted signal.The first and the second transmitting electrodes are arrangedalternatively so that their number is the same as that of the holes, andall the first transmitting electrodes coincide with the holes of therotor only once every rotation of the rotor. Just before and after thecoincidence, all the second transmitting electrodes coincide with theholes of the rotor.

On the other hand, in this example of the present invention, also thefollowing constitution is preferable. The transmitting electrodestransmit two kinds of the transmitted signals, and the electrodes on theboundary portions opposed to the detecting holes have smaller area thanthat of the electrodes on the other portion.

It is desirable that the transmitting electrodes transmit two kinds ofthe transmitted electrodes, the electrode shapes on at least the twoboundary portions are different from each other, the rotating directionas well as the mechanical position information is detected. Further, thetransmitting electrodes transmit the two kinds of the transmittedsignals, and the shapes of transmitting electrodes, having differentangles with respect to the rotating direction with the rotating axis ofthe rotor being the center, is different from each other, and thesetransmitting electrodes are provided in at least three or more places.

On the other hand, in the example of the present invention, thetransmitted signals are three kinds of signals with different phases,and the three transmitting electrodes are provided so as to transmit thethree transmitted signals simultaneously. Further, the firsttransmitting electrode outputs the first transmitted signal, and thesecond transmitting electrode outputs the second transmitted signaldifferent from the first transmitted signal.

On the other hand, in this example of the present invention, the firsttransmitting electrodes output the first transmitted signals, the secondtransmitting electrodes output the second transmitted signals differentfrom the first transmitted signals, and the fist transmitting electrodesand the second transmitting electrodes are arranged alternatively in therotating direction with the rotating axis of the rotor being the center.The first transmitting electrodes have different electrode areas.

In this example of the present invention, the first transmittingelectrodes output the first transmitted signals, and the secondtransmitting electrodes output the second transmitted signals differentfrom the first transmitted signals. Further, the third transmittingelectrodes output the third transmitted signals different from the firstand the second transmitted signals. The first, the second and the thirdtransmitted signals are transmitted simultaneously.

In another basic constitution in this example of the present invention,for example, the electric watch having the detecting mechanism fordetecting the position information of the rotating member to be measuredincludes a transmitting circuit, the transmitting electrode, signalmodulating means, the receiving electrode, a receiving circuit. Thetransmitting circuit generates a plurality of transmitted signals. Theoutput signal from the transmitting circuit is applied to thetransmitting electrode. The receiving electrode receives a signal fromthe transmitting electrode. The rotor is provided between thetransmitting electrode and the receiving electrode, and modulates thetransmitted signal output from the transmitting electrode. The modulatedsignal received by the receiving electrode is input to the receivingcircuit and is amplified by the receiving circuit. The referenceposition of the rotor is detected based on the phase change of thereceived signal. One of the transmitting electrode and the receivingelectrode may be constituted by a printed-wiring board.

In another constitution, the electric watch having the detectingmechanism for detecting the position information of the rotating memberto be measured includes a transmitting circuit, the transmittingelectrode, signal modulating means, the receiving electrode, a receivingcircuit. The transmitting circuit generates a plurality of transmittedsignals. The output signal from the transmitting circuit is applied tothe transmitting electrode. The receiving electrode receives a signalfrom the transmitting electrode. The rotor is provided between thetransmitting electrode and the receiving electrode, and modulates thetransmitted signal output from the transmitting electrode. The modulatedsignal received by the receiving electrode is input to the receivingcircuit and is amplified by the receiving circuit. The referenceposition of the rotor is detected based on the phase change of thereceived signal. The receiving electrode may be formed by aprinted-wiring board, and an integrated circuit including the receivingcircuit may be mounted on the printed-wiring board.

Further, the electric watch may be constituted so that at least an uppersurface or a lower surface of the received signal pattern, whichconnects the receiving electrode formed on the printed-wiring board withthe integrated circuit having the receiving circuit, is shielded by apattern as a ground electrode

Further, in another constitution of the electric watch, the electricwatch having the detecting mechanism for detecting the positioninformation of the rotating member to be measured includes atransmitting circuit, the transmitting electrode, signal modulatingmeans, the receiving electrode, a receiving circuit. The transmittingcircuit generates a plurality of transmitted signals. The output signalfrom the transmitting circuit is applied to the transmitting electrode.The receiving electrode receives a signal from the transmittingelectrode. The rotor is provided between the transmitting electrode andthe receiving electrode, and modulates the transmitted signal outputfrom the transmitting electrode. The modulated signal received by thereceiving electrode is input to the receiving circuit and is amplifiedby the receiving circuit. The reference position of the rotor isdetected based on the phase change of the received signal. The receivingelectrode or the transmitting electrode may be an electricallyconductive film formed on the surface of a supporting member of therotor.

As is clear from the above explanation, in the position detecting systemof the electric watch according to the respective examples of thepresent invention, the transmitting electrodes 331 and 332 are arrangedso as to be divided by 180°. They are opposed to the approximatelyentire periphery of the rotating surface of the detecting wheel 336 ofthe signal modulating means composing the position detecting system. Inanother manner, the transmitting electrode 331 is made to be small, thetransmitting electrode 332 is made to be large, and the receivingelectrode 335 is disposed so as to oppose to the entire periphery of therotating surface of the detecting wheel 336. As a result, even if thedetecting wheel 336 is in any position, the phase angle can be detected,and further the phase changes twice per rotation. For this reason, ascompared with the case where the transmitting electrode and thereceiving electrode are arranged on a portion opposed to the detectingwheel 336, the detecting accuracy is improved, and the circuitconfiguration becomes very simple.

In the present invention, the five detecting holes 342, 343, 344, 345and 346 are provided on the rotating surface of the detecting wheel 336so as to form different angles each other with the rotating axis beingthe center. The five transmitting electrodes 354, 355, 356, 357 and 358for transmitting the transmitted signal φB and the five transmittingelectrodes 364, 365, 366, 367 and 368 for transmitting the transmittedsignal φA are arranged alternatively. The transmitting electrodes areformed into the cord shape so that all the detecting holes match all theboundary portions between the transmitting electrodes only once perrotation of the rotating wheel 336. The detection is made in fiveplaces. As a result, the amplitude of the received signal becomes largerthan that in the case where the detection is made in one place, and thusthe detecting ability is heightened, thereby enabling more accuratedetection.

Further, in the present invention, the electrode area of the boundaryportion between the transmitting electrodes 331 and 332 is set to besmaller than that in the other portion, so that the change in the phaseof the received signal from the receiving electrode due to the rotationof the detecting wheel becomes large. For this reason, the positiondetecting ability can be improved.

On the other hand, in the present invention, the electrode shapes on thetwo boundary portion between the transmitting electrodes 331 and 332 aredifferent from each other, so that the gradient of the phase change onthe first boundary portion is different from the gradient of the phasechange on the second boundary portion As a result, the rotatingdirection as well as the mechanical position information of thedetecting wheel can be detected.

In the present invention, the transmitting electrodes have such a shapethat the transmitting electrodes are different from each other and havedifferent angles each other, so that change patterns of the phase in theregular rotation and the reverse rotation due to the rotation of thedetecting wheel are different from each other. In this state, thedetection is made, so that the rotating direction as well as themechanical position information can be detected.

Further in the present invention, the two transmitted signals whosephases are different by π, and the one transmitted signal with a justmiddle phase between the phases of the two transmitted signals are usedand the phase change of the received signal can be theoreticallyenlarged to π by one rotation of the detecting wheel as the rotor.

In the present invention, the transmitting electrode and the receivingelectrode are formed as circuit patterns on the printed board, so as tobe formed freely into desirable shapes. This method is more realisticand practical than a method of forming the electrodes using a metalplate or the like. The board can be a glass epoxy board or an FPC board.In the examples, the transmitting electrode and the receiving electrodeare formed on the printed-wiring board, but only one of the transmittingelectrode and the receiving electrode may be formed on theprinted-wiring board.

Further in the present invention, the integrated circuit (IC) is mountedon the circuit board forming the receiving electrode so as to form acircuit block, so that the receiving electrode and the receiving circuitcan be connected by the shortest length. This can prevent the weakreceived signal from being influenced by external noise and by thetransmitted signal, thereby preventing the detecting ability from beingdeteriorated.

On the other hand, in the present invention, the upper and lowersurfaces of the received signal pattern electrically connect theintegrated circuit having the receiving electrode and the receivingcircuit, are shielded. As a result, the receiving electrode is hardlyinfluenced by the external noise and the transmitted signal, therebypreventing deterioration of the detecting ability. It is also effectivethat only a side surface of a both-sided board opposite to the receivedsignal is shielded, but the effect is the best when a laminated board isutilized so that its both upper and lower surfaces throughout thelaminated board are shielded against the received signal.

FIFTEENTH EXAMPLE

The position detecting system of the electric watch according to afifteenth example of the present invention is explained below withreference to FIGS. 52 to 57.

In the fifteenth example of the present invention, the electric watchhaving the detecting mechanism for detecting the position information ofthe rotating member to be measured basically includes the transmittingcircuit, a plurality of transmitting electrodes, the receivingelectrode, the rotor, and a relay electrode. The transmitting circuitoutputs a plurality of transmitted signals. The transmitting electrodesare formed on an insulating member and transmit the transmitted signals.The receiving electrode is formed on the insulating member. The rotor isprovided so as to be opposed to the transmitting electrodes and thereceiving electrode. The relay electrode is formed on the rotatingsurface of the rotor so as to be opposed to the transmitting electrodesand the receiving electrode. More concretely, the electric watch havingan angle rotating position detecting mechanism of the rotating member tobe measured in the watch includes the transmitting circuit, a pluralityof transmitting electrodes, the receiving electrode, the rotor, therelay electrode, a position detecting circuit. The transmitting circuitoutputs a plurality of transmitted signals. The transmitting electrodesare formed on the insulating member and transmit the transmittedsignals. The receiving electrode is formed on the insulating member. Therotor is mechanically coupled with the rotating member to be measured soas to rotate. The relay electrode is arranged on the rotor so as to beopposed to the transmitting electrodes and the receiving electrode. Theposition detecting circuit receives a propagated signal induced by therelay electrode as the received signal via the receiving electrode, andinputs the received signal therein so as to detect the mechanicalrotating position of the operating mechanism.

The mechanical constitution of the position detecting system in theelectric watch according to the fifteenth example of the presentinvention is explained with respect to FIGS. 52 and 53. The numeral 402designates a rotor, the numeral 403 designates a stator, and they aswell as a coil, not shown, compose a step motor as the power source ofthe electric watch. The numeral 404 designates the fifth wheel fordecelerating the rotation of the rotor 402, and the fifth wheel 404decelerates and propagates the rotation to a fourth wheel, not shown,for driving the second hand.

The numeral 405 designates the detecting wheel as the rotor constitutedby an insulator made of plastic or the like, and the rotation isdecelerated and propagated from the fifth wheel 404 to the detectingwheel 405 at a reduction ratio which is the same as a reduction ratiofrom the fifth wheel 404 to the fourth wheel, not shown. The numeral 406designates the relay electrode made of a plate-shaped electricallyconductive member arranged on the rotating surface 405 a of thedetecting wheel 405, and its shape spreads to three directions radiallyas shown by slanted lines in FIG. 53( a). The numeral 407 designates anaxle of the detecting wheel 405 composed of the conductor.

The numeral 414 designates a ground plate constituted by an insulatormade of plastic or the like, and the numeral 415 designates a wheeltrain receiver constituted by an insulator made of plastic or the like.The ground plate 414 and the wheel train receiver 415 support the wheeltrain composed of the rotor 402, the fifth wheel 404 and the like, andthe axle 407 of the detecting wheel 405.

The numeral 408 designates a printed board made of an insulating memberarranged adjacently to the detecting wheel 405, and the numeral 409designates an axle hole of the printed board 408 through which the axle407 of the detecting wheel 405 is inserted. The numeral 410 designatesthe integrated circuit (hereinafter, IC) including the respectivecontrol circuits mounted on the printed board 408. The numeral 411designates the receiving electrode made of copper foil formed into acircular shape with the axle hole 409 of the printed board 408 being thecenter. The receiving electrode 411 is electrically connected with theIC 410 by a received signal line 411 a shown in FIG. 53( b).

The numerals 412 and 413 designate two sets of the transmittingelectrodes which are formed by copper foil on the surface of the printedboard 408 and output a plurality of transmitted signals. Its detailedconstitution is shown in FIG. 53( b). One transmitting electrode 412 iscomposed of three transmitting electrodes 412 a, 412 b and 412 c, eachbeing arranged in approximately fan-shaped patterns. The transmittingelectrodes 412 a, 412 b and 412 c are electrically connected by atransmitting electrode connecting line 412 d which passes through therear surface of the printed board 8. They are connected with the IC 410by a transmitted signal line 412 e. The other transmitting electrode 413is composed of three transmitting electrodes 413 a, 413 b and 413 c,each being arranged in approximately fan-shaped patterns. They areelectrically connected with each other by a transmitting electrodeconnecting line 413 d formed on the printed board 408, and are connectedwith IC 410 by a transmitted electrode connecting line 413 e.

The transmitting electrodes 412 a, 412 b, 412 c, 413 a, 413 b and 413 care arranged and formed so as to surround the circular receivingelectrode 411 in a position relationship of a concentric circle.Further, the detecting wheel 405 is arranged so that the axle 407pierces the axle hole 409 of the printed board 408. For this reason, therelay electrode 406 arranged on the rotating surface of the detectingwheel 405, the transmitting electrodes 412 a, 412 b, 412 c, 413 a, 413 band 413 c and receiving electrode 411 formed on the printed board 408are arranged so as to be opposed to each other. They adjoin each otherin a non-contact manner.

As a result, the transmitting electrodes 412 a, 412 b, 412 c, 413 a, 413b and 413 c and the receiving electrode 411 are electricallycapacity-coupled with the relay electrode 406 provided on the detectingwheel 405.

The outline of the basic operation of the position detecting system inthe electric watch according to the present invention is explained belowwith reference to FIGS. 52 and 53. When a driving signal (not shown) isoutput from IC 410 to the coil of the step motor, not shown, every onesecond, the rotor 402 starts to rotate. Its rotating force isdecelerated and transmitted to the fifth wheel 404. Further, therotating force is transmitted to the detecting wheel 405 and the fourthwheel, not shown, at the same reduction ratio, and the detecting wheel405 and the fourth wheel rotates by 6° every one second. On the otherhand, the IC 410 has a time counting circuit (not shown) for adding acounted value every time when the rotor 402 is driven, a calendarcircuit (not shown), and the like. The time and calendar information areelectrically held in the IC 410.

When the detecting wheel 405 rotates, the relay electrode 406 on therotating surface 405 a of the detecting wheel 405 also rotates by 6°every one second while the transmitting electrodes 412 a, 412 b, 412 c,413 a, 413 b and 413 c and the receiving electrode 411 and the relayelectrode 406 adjoining and being in the non-contact manner. As aresult, since the adjoining area between the relay electrode 406 and thetransmitting electrodes 412 a, 412 b, 412 c, 413 a, 413 b and 413 cchanges, the states of electrical capacitive coupling between both theelectrodes changes every one second. Since, however, the adjoiningsurface of the relay electrode 406 and the receiving electrode 411 iscircular, even when the relay electrode 406 rotates, the adjoining areathereof does not change, and neither does the capacitive coupling.

The electrical constitution and the electrical operation of the positiondetecting system in the electric watch of the present invention areexplained below with reference to FIG. 54. FIG. 54 is a block diagramillustrating the electrical constitution of the position detectingsystem. The constitution of the position detecting system is composed ofan oscillation dividing circuit 420, the transmitting circuit 423, thereceiving electrode 411, the transmitting electrodes 412 and 413, thedetecting wheel 405, the relay electrode 406, a receiving circuit 424composed of an amplifying circuit, a reference signal generating circuit428, and a position detecting circuit 430. The oscillation dividingcircuit 420 generates output signals. The transmitting circuit 423 iscomposed of two bandpass filter amplifying circuits (hereinafter, BPFamplifying circuits) 421 and 422. The relay electrode 406 is arranged onthe detecting wheel 405. The reference signal generating circuit 428 iscomposed of capacitors 425 and 426 and the amplifying circuit 427.

The electrical connecting relationship of the position detecting systemis explained below with reference to FIG. 54. The oscillation dividingcircuit 420 outputs various control signals (not shown) and drivingsignals (not shown), and outputs an output pulse Pa(+45′) whose phaseadvances by 45° and an output pulse Pb(−45°) whose phase delays by 45°(hereinafter, Pa (+45°) is designated by Pa, and Pb (−45°) is designatedby Pb. The input signal of the BPF amplifying circuit 421 of thetransmitting circuit 423 is the pulse Pa and the BPF amplifying circuit421 outputs the transmitted signal φA. The input signal of the BPFamplifying circuit 422 of the transmitting circuit 423 is the pulse Pband the BPF amplifying circuit 422 outputs the transmitted signal φB.

The transmitted signal φA is input into the transmitting electrode 412and the capacitor 425, and the transmitted signal φB is input into thetransmitting electrode 413 and the capacitor 426. The receivingelectrode 411 outputs the received signal φC via the transmittingelectrode 406, and the received signal φC is input to the receivingcircuit 424 and the receiving circuit 424 outputs a received pulsesignal Pc. A synthesized signal φab obtained by synthesizing the twotransmitted signals φA and φB via the two capacitors 425 and 426 isinput to the amplifying circuit 427 of the reference signal generatingcircuit 428, and the amplifying circuit 427 outputs a reference signalPab (0°) whose phase does not advance or delay (hereinafter, Pab (0°) isdesignated by Pab). The received pulse signal Pc and the referencesignal pab are input to the position detecting circuit 430 and theposition detecting circuit 430 outputs a position signal Pd.

The electrical operation of the position detecting system is explainedbelow with reference to FIG. 54. The oscillation dividing circuit 420outputs the two output pulses Pa and Pb whose phases are shifted by π/2by an internal quartz oscillating circuit (not shown) and a logiccircuit (not shown). The output pulses Pa and Pb are input to the twoBPF amplifying circuits 421 and 422 of the transmitting circuit 423,respectively, and in the BPF amplifying circuits 421 and 422, ahigh-frequency component is removed and only a fundamental wavecomponent is amplified. The BPF amplifying circuits 421 and 422 generatethe two transmitted signals φA and φB which are sine waves and phasedifference between them is π/2.

The generated two transmitted signals φA and φB are transmitted from thetransmitting electrodes 412 and 413. Since the transmitting electrodes412 and 413 are high-impedance loads having extremely smallelectrostatic capacities, the power consumption of the transmittingcircuit 423 is very small. As mentioned above, since the detecting wheel405 rotates at the rotating angle of 6° per second, the electriccapacity coupling between the relay electrode 406 and the transmittingelectrodes 412 and 413 changes according to the rotation of thedetecting wheel 405. As a result, a relay signal which is modulatedaccording to the rotation of the detecting wheel 405 is induced on therelay electrode 406.

The receiving electrode 411 adjoins the relay electrode 406 in thenon-contact manner as mentioned above so that the electrical capacitivecoupling is carried out. Even if the detecting wheel 405 rotates, thestates of the electrical capacitive coupling does not change. As aresult, the propagated signal induced by the relay electrode 406 is notmodulated by receiving electrode 411, which is electricallycapacitive-coupled with the relay electrode 406, and is transmitted tothe receiving electrode 411 as the received signal φC. Further, thereceived signal φC is amplified so as to be saturated by the receivingcircuit 424, and the received pulse signal Pc which holds the phaseinformation of the received signal φC is generated.

The operation of the reference signal generating circuit 428 forgenerating the reference signal Pab is explained below. The transmittedsignal φA whose phase advances by 45° and the transmitted signal φBwhose phase delays by 45° are input to capacitors 425 and 426 of thereference signal generating circuit 428, and generates the synthesizedsignal φab. Since capacity values of the capacitors 425 and 426 areequal with each other, however, the phase of the synthesized signal φabhas a sine wave with a phase angle of 0° which is a middle point betweenthe phases of the two transmitted signals φA and φB. The synthesizedsignal φab is amplified so as to be saturated by the amplifying circuit427, and the amplifying circuit 427 generates the reference signal Pabwhich is a pulse signal with phase angle of 0°.

The operation of the position detecting circuit 430 is explained belowwith reference to FIG. 54. The position detecting circuit 430 iscomposed of a D-type flip-flop 430 a (hereinafter, D-FF) as one example.The received pulse signal Pc is input into a data input terminal D ofthe D-FF 430 a, and the reference signal Pab is input into a clockterminal CL of the D-FF 430 a. Further, an output terminal Q of the D-FF430 a outputs the position signal Pd.

When the phase of the received pulse signal Pc input into the data inputterminal D of the D-FF 430 a advances with respect to the phase of thereference signal Pab input into the clock terminal CL, a logical levelof the output terminal Q becomes logic “H”. When the phase of thereceived pulse signal Pc input into the data input terminal D delaysfrom the phase of the reference signal Pab input into the clock terminalCL, the logical level of the output terminal Q becomes logic “L”. As aresult, the advance and delay of the phase of the received pulse signalPc with respect to the reference signal Pab can be obtained by thelogical level of the position signal Pd.

A change in the position relationship between the relay electrode 406and the transmitting electrodes 412 and 413, and a change in the phaseof the received signal φC according to the change in the positionrelationship are explained below. FIG. 55 is a plan view illustratingthe change in the position relationship between the relay electrode 406and the transmitting electrodes 412 and 413 when the relay electrode 406arranged on the detecting wheel 405 rotates once about the axle 407.FIG. 55(A) to 55(I) illustrate the change in the position relationshipat every 40° step of one rotation. As mentioned above, the transmittingelectrode 412 transmits the transmitted signal whose phase advances by45°, and the transmitting electrode 413 transmits the transmitted signalφB whose phase delays by 45°. The relay electrode 406 rotates to a rightdirection with respect to the transmitting electrodes 412 and 413.

In the state of FIG. 55( a), the two blade portions shown by slantedlines of the relay electrode 406 which spread to three directions areadjacently overlapped with the transmitting electrodes 412 a and 412 b,and the other blade portion is adjacently overlapped with thetransmitting electrode 413 b. As a result, the transmitting electrode412 for transmitting the transmitted signal φA is adjacently overlappedwith the relay electrode 406 with an area ratio which is twice as largeas the transmitting electrode 413 for transmitting the transmittedsignal φB. The relay signal which is induced by the relay electrode 406,therefore, becomes a synthesized wave of the transmitted signals A andB, but its synthesizing ratio becomes transmitted signal φA: thetransmitted signal φB=2:1, and thus the influence of the transmittedsignal φA is double. For this reason, the doubled influence of thetransmitted signal φA exerts on the phase of the transmitted signal, andthus the phase of the propagated signal becomes +15° with respect to thephase of the reference signal Pab which is 0°.

FIG. 55(B) illustrates a state that the relay electrode 406 rotates tothe right direction by about 40° from the state in FIG. 55(A). The twoblade portions of the relay electrode 406 which spread to the threedirections are adjacently overlapped with the transmitting electrodes412 a and 412 b, and the other blade portion is adjacently overlappedwith the transmitting electrode 413 a. As a result, the synthesizingratio of the relay signal induced by the relay electrode 406 becomes thetransmitted signal φA: the transmitted signal φB=2:1 similarly to FIG.55(A). Accordingly, phase of the relay signal becomes +15° with respectto the phase of the reference signal Pab which is 0°. Hereinafter, inthe position relationships in FIGS. 55(C), (G), (H) and (I), thesynthesizing ratio of the relay signal becomes the transmitted signalφA: the transmitted signal φB=2:1 similarly. For this reason, when thephase of the reference signal Pab is 0° as the reference, the phase ofthe propagated signal becomes +15°.

In the state of FIG. 55(D), all of the blade portions of the relayelectrode 406 which spread to the three directions are adjacentlyoverlapped with the transmitting electrodes 412 a˜412 b and 412 cbelonging to the transmitting electrode 412. The relay signal is,therefore, influenced only by the transmitted signal φA, and its phasebecomes +45° which is equal with the transmitted signal φA. Similarly,in the state of FIG. 55(F), all of the blade portions of the relayelectrode 406 which spread to the three directions are adjacentlyoverlapped with the transmitting electrodes 412 a, 412 b and 412 cbelonging to the transmitting electrode 412. The relay signal is,therefore, influenced only by the transmitted signal φA, and its phasebecomes +45° which is equal with the transmitted signal φA.

In addition, in the state of FIG. 55(E), all of the blade portions ofthe relay electrode 406 which spread to the three directions areadjacently overlapped with the transmitting electrodes 413 a, 413 b and413 c belonging to the transmitting electrode 413. The propagated signalis, therefore, influenced only by the transmitted signal φB, and itsphase becomes −45° which is equal with the transmitted signal φB. Asmentioned above, the propagated signal induced by the relay electrode406 is propagated to the receiving electrode 411 as the transmittedsignal φC without being modulated. For this reason, the phaseinformation of the received signal φC is equal to the phase informationof the propagated signal.

The explanation in FIG. 55 describes the change in the phase in the caseof the ideal constitution without leak, but an actual phase change isslightly small.

FIG. 56 illustrates the change in the phases of the transmitted signalsφA and φB and the received signal φC due to the change in the positionrelationships between the relay electrode 406 and the transmittingelectrodes 412 and 413 shown in FIG. 55. FIG. 56( a) illustrates thephase relationship between the transmitted signals φA, φB and φC whenthe phase of the received signal φC shown in FIG. 55(A) is +150. FIG.56( b) illustrates the phase relationship between the transmittedsignals φA, φB and φC when the phase of the received signal φC shown inFIGS. 55(D) and 55(F) is +45° which is equal with the phase of thetransmitted signal φA. FIG. 56( c) illustrates the phase relationshipbetween the transmitted signals φA, φB and φC when the phase of thereceived signal φC shown in FIG. 55(E) is −45° which is equal with thephase of the transmitted signal φB. The received signal φC becomes asignal obtained by modulating the transmitted signals φA and φBaccording to the position relationship between the relay electrode 406and the transmitting electrodes 412 and 413.

FIG. 57( a) is a graph in which the relationship between a rotatingamount of the detecting wheel 405 and the phase of the received signalφC is sampled every movement of the hand per second. The rotating amount(second) of the detecting wheel 405 is plotted along the X axis and thephase angle of the received signal φC is plotted along the Y axis. Blackcircles on the graph show the phase of the received signal φC persecond, and A to I which is described on a lower portion of the graphcorrespond to the positions of the relay electrode 406 shown in FIGS.55(A) to 55(I).

That is to say, the position of the detecting wheel 405 shown in FIG.55(A) is a starting point on the graph of FIG. 57( a) (namely, a leftcorner). When the detecting wheel 405 is rotated to the right persecond, the phase of the received signal φC at the period correspondingto FIGS. 55(A) to 55(C) is maintained at +15°, and the phase of thereceived signal φC becomes +45° at the period corresponding to FIG.55(D). The phase of the received signal φC is inverted to be −45° at theperiod corresponding to FIG. 55(E), and the phase of the received signalφC is again inverted so as to be +45° at the period corresponding toFIG. 55(F). The phase of the received signal φC is again maintained at+15° at the period after FIG. 55(G).

As explained in FIG. 55, FIG. 57( a) shows the change in the phase inthe case of the ideal constitution without leak, and the actual phasechange is slightly small.

FIG. 57( b) illustrates a waveform of the position signal Pd which isthe output from the position detecting circuit 430 corresponding to thephase change of the received signal φC shown in FIG. 57( a). Theposition signal Pd outputs the logic “H” at the period that the receivedsignal φC advances to the plus side, and outputs the logic “L” at theperiod that the received signal φC delays to the minus side. For thisreason, when the detecting wheel is moved from D to E shown in FIG. 57(a), the position signal Pd is changed from the logic “H” into the logic“L”. When the detecting wheel position number is moved from E to F, theposition signal Pd is changed from the logic “L” into the logic “H”. Thelogic change of the position signal Pd is captured, accordingly, theaccurate rotating position of the detecting wheel 405 can be detectedwith accuracy of one second unit.

The position detecting circuit 430 detects the phase per movement of thehand every one second and output the position signal Pd. When thedetecting wheel 405 stops in the vicinity where the phase of thereceived signal φc just passes through 0° and the phase is detected,advance and delay occurs instantaneously and mainly in the vicinitywhere the phase is 0° due to the jolting of the wheel train and thedetecting wheel 405. This involves the risk of mis-detection of theposition. Even if slight jolting is present on the wheel train and thedetecting wheel, therefore, the phases of the reference signal Pab andthe transmitted signals φA and φB are finely adjusted in order toprevent the mis-detection of the position. In such a manner, theadjustment may be made so that the positions of the black circles inFIG. 57( a) which are measuring points of the phase do not come to thevicinity of the phase of 0°.

In FIG. 57( a), the black circle positions which pass through the phaseof 0° are in the vicinity of +10° and −10° because this adjustment ismade. As a result, even if the wheel train and the detecting wheel jolt,the position is not mis-detected. Further, the position detecting systemof the present invention does not detect a change in an absolute valueof the electrostatic capacity value and an absolute value of the phaseangle, but detects a relative change in phase on the basis of thetransmitted signals with different phases. For this reason, influencesof temperature change, aged deterioration and the other disturbances arecanceled, thereby detecting the position with high accuracy and highreliability.

The time correcting method of the electric watch using the positionsignal Pd which is the output from the position detecting circuit 430 isexplained below. For example, the position of the detecting wheel 405 atthe moment when the position signal Pd in FIG. 57( b) is changed fromthe logic “L” into the logic “H” is determined a zero second originalpoint, and the secondhand is attached to the fourth wheel so as to be12:00:00. In the position of the zero second original point, the timecounting circuit (not shown) for storing the electric holding timeincluded in the IC 410 is reset, and the electric watch is started fromthat state.

The electric watch continuously moves the hand per second, and the timecounting circuit in the IC 410 also counts a number per second. For thisreason, the display position of the hand as the mechanical holding timedoes not shift from the information of the time counting circuit forstoring the electric holding time. When the one-second hand movement ofthe train wheel is mis-operated due to the impact and the otherdisturbances, the display position of the hand does not match the timeinformation of the time counting circuit in the IC 410.

The control circuit (not shown) of the IC 410 always monitors the timeinformation of the time counting circuit and the zero second originalpoint represented by the position signal Pd output from the positiondetecting circuit 430. When the time information of the time countingcircuit does not match the zero second original point represented by theposition signal Pd, the rotor 402 is rotated to the regular or reversedirection, and the correction is made so that the time information ofthe time counting circuit matches the zero second original pointrepresented by the position signal Pd.

According to the fifteenth example, the transmitting electrodes and thereceiving electrode are formed on the surface of the insulating membersuch as one and the same printed board or the like, and the position ofthe wheel train is detected by the phase detecting means utilizing thechange in the electrical capacitive coupling between the transmittingelectrodes, the receiving electrode and the relay electrode arranged onthe detecting wheel. As a result, the time difference between themechanical holding time and the electrical holding time in the electricwatch is detected, the time can be corrected into proper time. Further,the transmitting electrodes and the receiving electrode are formed onthe surface of one and the same insulating member, and the phasedetecting means, which utilizes the change in the electrical capacitivecoupling between the above electrodes and the relay electrode arrangedon the detecting wheel, is adopted. As a result, the constitution of theposition detecting system is simple, and thus the wristwatch accordingto the present invention system can be thin, and the cost of theposition detecting system can be reduced. Further, the wristwatch havingthe month-end automatic correcting function can be constituted by usingthe system for the mechanical position detection of the day plate andthe week plate.

In this example, according to the above-mentioned constitution, thetransmitting electrodes and the receiving electrode are formed on theinsulating member such as one printed board, and the relay electrode isarranged on the rotor, which is mechanically coupled with the operatingmechanism and is rotated, so as to be opposed to the transmittingelectrodes and the receiving electrode. The propagated signal induced bythe relay electrode is received as the received signal by the receivingelectrode, and the received signal is input to the phase detectioncircuit so that the mechanical rotating position of the operatingmechanism is detected. For this reason, the position detecting system,which does not require a lot of energy, is not deteriorated with age andhas high reliability, can be constituted.

Further, since the transmitting electrodes and the receiving electrodeare formed on the surface of one and the same insulating member, anexcessive insulating member such as a printed board is not required, andthe constitution of the position detecting system can be simplified.Further, the system can be thinned, and the cost of the positiondetecting system can be reduced.

SIXTEENTH EXAMPLE

The position detecting system of the electric watch according to asixteenth example of the present invention is explained below withreference to FIG. 58.

FIG. 58 is a plan view illustrating the constitution of the transmittingelectrodes and the receiving electrode according to the sixteenthexample of the present invention. The explanation of the portion commonwith FIG. 53( b) is omitted. The numeral 417 designates a groundelectrode electrically grounded, and it is arranged in a gap of theboundary portion between the transmitting electrodes 412 a, 412 b, 412c, 413 a, 413 b and 413 c and the receiving electrode 411. Further, theground electrode 417 is arranged so as to cover a periphery portion ofthe received signal line 411 a for propagating the received signal φC.

According to the sixteenth example, the ground electrode 417 is arrangedin the gap of the boundary portion between the transmitting electrodes412 a, 412 b, 412 c, 413 a, 413 b and 413 c and the receiving electrode411, so that the receiving electrode 411 and the received signal line411 a are shielded by the ground electrode 417 and are separatedelectrically. For this reason, the transmitted signals φA and φBtransmitted from the transmitting electrodes 412 a, 412 b, 412 c, 413 a,413 b and 413 c do not leak to the receiving electrode 411, therebypreventing noise from being mixed in the receiving electrode 411 and thereceived signal line 411 a. As a result, the S/N ratio of the receivedsignal φC induced by the receiving electrode 411 can be improvedgreatly.

SEVENTEENTH EXAMPLE

The position detecting system of the electric watch according to aseventeenth example of the present invention is explained below withreference to FIG. 59.

FIG. 59 is a partially sectional view of the position detecting systemof the electric watch, and the degree of the capacitive coupling betweenthe relay electrode and the receiving electrode is improved. Theexplanation of the portion common with FIG. 52 is omitted.

In FIG. 59, the numeral 407 a designates a relay axle portion composedof an electrically conductive member which is integral with the axle407, and the relay axle portion 407 a is electrically connected with therelay electrode 406 arranged on the rotating surface 405 a of thedetecting wheel 405. The numeral 411 b designates a through hole portioncomposed of an electrically conductive member which is formed on aninner surface of the axle hole 409 of the printed board 408 and iselectrically connected with the receiving electrode 411. The throughhole portion 411 b adjoins a peripheral surface 407 b of the relay axleportion 407 a in a non-contact manner.

The operation in the seventeenth example of the present invention isexplained below. The relay signal (not shown) from the transmittingelectrodes 412 and 413 induced by the relay electrode 406 is propagatedalso to the relay axle portion 407 a electrically connected with therelay electrode 406. The peripheral surface 407 b of the relay axleportion 407 a is capacitive-coupled with the through hole portion 411 bformed on the axle hole 409. For this reason, the propagated signal ispropagated as the received signal φC from the peripheral surface 407 bof the relay axle portion 407 a to the through hole portion 411 b.

On the other hand, as explained in the operation in the fifteenthexample, the relay signal is propagated as the received signal φC fromthe relay electrode 406 also to the receiving electrode 411 formed onthe printed board 408. The received signal propagated by the relay axleportion 407 a is designated by φC1, and the received signal propagatedby the relay electrode 406 is designated by φC2. The received signal φCinput into the IC 410 is obtained in such a manner that φC=φC1+φC2. As aresult, the level of the received signal φC rises, and the S/N ratio isimproved, thereby effectively preventing the mis-detection of theposition.

The relay signal is propagated also to the axle 407 of the detectingwheel 405 because the axle 407 is made of the electrically conductivemember. The ground plate 414 and the wheel train receiver 415 whichreceives the upper and lower portions of the axle 407 are, however, madeof the insulating member such as plastic. For this reason, noise is notmixed in the propagated signal from another parts via the ground plate414 and the wheel train receiver 415. Further, when the ground plate 414and the wheel train receiver 415 are made of the electrically conductivemember such as metal, their bearing portions may be received by agemstone or the like which is the insulating member.

In addition, in the case where the miniaturization of the wrist watch isstrongly demanded and thus the outer size of the detecting wheel 405should be as small as possible, the seventeenth example is extremelyeffective. That is to say, the receiving electrode 411 is eliminatedfrom the printed board 408, and the received signal φC is received onlyby the through hole portion 411 b of the axle hole 409. As a result, therelay electrode 406 on the rotating surface of the detecting wheel 405may be opposed only to the transmitting electrodes 412 and 413, thusmaking the outer shape of the detecting wheel 405 small. For thisreason, the wrist watch can be effectively miniaturized.

According to the seventeenth example, not only the received signalpropagated between the relay electrode 406 and the receiving electrode411 but the received signal propagated between the peripheral surface407 b of the relay axle portion 407 a and the through hole portion 411 bformed on the axle hole 409 is added. For this reason, the level of thereceived signal rises, and the S/N ratio is improved, thereby preventingthe mis-detection of the position. Further, when this example iscombined with the sixteenth example, the S/N ratio of the receivedsignal is further improved, thereby further heightening the accuracy ofthe position detection. As a result, the position detecting system withexcellent reliability can be provided.

EIGHTEENTH EXAMPLE

The position detecting system of the electric watch according to theeighteenth example of the present invention is explained below withreference to FIG. 60.

FIG. 60 is a partially sectional view of the position detecting systemof the electric watch, and the explanation of the portion common withFIG. 52 is omitted. The numeral 416 designates the wheel train receivercomposed of an insulating member such as plastic similarly to thefifteenth example. An electrically conductive film is formed on a lowersurface portion 416 a of the wheel train receiver, and one portion ofthe electrically conductive film serves as the transmitting electrodes412 and 413 and the receiving electrode 411. Further, the IC 410 isdirectly mounted on the lower surface portion 416 a of the wheel trainreceiver, and the IC 410 are connected with the transmitting electrodes412, 413 and the receiving electrode 411 and the like by theelectrically conductive film.

According to the eighteenth example, since the printed board 408 in thefifteenth example is not necessary, the electric watch can be thinned,and the cost of the parts can be reduced. The wheel train receiver 416is replaced by a printed board made of a glass-mixed member or the likewith less warp, and the transmitting electrodes 412 and 413 and thereceiving electrode 411 can be formed by a normal etching technique.

NINETEENTH EXAMPLE

The position detecting system of the electric watch according to anineteenth example of the present invention is explained below withreference to FIG. 61.

FIG. 61 is a plan view illustrating the position relationship betweenthe transmitting electrode, the receiving electrode and the relayelectrode according to the nineteenth example of the present invention.In FIG. 61( a), the numeral 440 designates the printed board composed ofthe insulating member, and the numeral 440 a designates the axle holeprovided on the printed board 440. The numerals 441 a and 441 b are thetransmitting electrodes made of copper foil or the like havingapproximately fan shape. The transmitting electrode 441 a transmits thetransmitted signal φA, and the transmitting electrode 441 b transmitsthe transmitted signal B. The numeral 442 is the receiving electrodemade of copper foil or the like having an approximately fan shape, andit is positioned between the transmitting electrodes 441 a and 441 b.

In FIG. 61( b), the numeral 443 designates the detecting wheel composedof the insulating member, and the numeral 443 a designates the axle. Thenumeral 444 designates the relay electrode composed of the electricallyconductive member having an approximately fan shape, and it is arrangedon the rear surface of the detecting wheel 443. The axle 443 a of thedetecting wheel 443 is inserted into the axle hole 440 a of the printedboard 440, and the detecting wheel 443 rotates in proximity to the relayelectrode, the transmitting electrodes 441 a, 441 b and the receivingelectrode 442 with the non-contact manner. For this reason, theelectrical capacitive coupling between the relay electrode 444 and thetransmitting electrodes 441 a and 441 b and the electrical capacitivecoupling between the relay electrode 444 and the receiving electrode 442is changed according to the rotation of the detecting wheel 443.

FIGS. 61( c) to 61(f) illustrate a change in the position relationshipbetween the relay electrode 444 of the detecting wheel 443 and thetransmitting electrodes 441 a, 441 b and the receiving electrode 442. Inthe state of FIG. 61( c), the relay electrode 444 is arranged so as tocross over both of a part of the transmitting electrode 441 a and a partof the receiving electrode 442, and the received signal φC, whose phaseadvances by 45° similarly to the transmitted signal φA, is propagated tothe receiving electrode 442. In a state of FIG. 61( d), the relayelectrode 444 is arranged so as to entirely cover the receivingelectrode 442 and to cross over both of a part of the transmittingelectrode 441 a and a part of the transmitting electrode 441 b. Thereceived signal φC with phase angle of 0° obtained by synthesizing thetwo transmitted signals φA and φB is propagated to the receivingelectrode 442.

In addition, in a state of FIG. 61( e), the relay electrode 444 isarranged so as to cross over both of a part of the transmittingelectrode 441 b and a part of the receiving electrode 442, and thereceived signal φC, whose phase delays by 45° similarly to thetransmitted signal φB, is propagated to the receiving electrode 442.Further, in a state of FIG. 61( f), since the relay electrode 444 is notoverlapped with any one of the transmitting electrodes 441 a and 441 band the receiving electrode 442, the received signal φC is a non-signal.Since the phase detecting circuit 403 can detect the moment at which thephase angle of the received signal φC becomes 0°, it can detect themoment at which the detecting wheel 443 passes through the position inFIG. 61( d). As a result, this point can be determined as the zerosecond original point of the detecting wheel.

According to the nineteenth example of the present invention, there is adisadvantage such that the level of the received signal φC changesaccording to the rotating position of the detecting wheel 443, but theshape of the transmitting electrodes can be simplified. For this reason,the manufacturing cost can be reduced. Further, the shapes of thereceiving electrode 442 and the transmitting electrodes 441 a and 441 bare not limited to the shape similar to fan like shape, and they mayhave any shape as long as the received signal φC is modulated accordingto the rotation of the detecting wheel 443.

As is clear from the fifteenth to the nineteenth examples of the presentinvention, in the electric watch of the present invention, thetransmitting electrodes are arranged into the approximately fan shape onthe insulating member, and the receiving electrode is formed into thecircular shape on the surface of the insulating member where thetransmitting electrodes are formed. It is desirable that thetransmitting electrodes and the receiving electrode establish theconcentric position relationship.

According to this constitution, the transmitting electrodes formed intothe approximately fan shape and the receiving electrode formed into theapproximately circular shape establish the concentric positionrelationship. As a result, even if the relay electrode rotates, itsadjacent area does not change, and the capacitive coupling does notchange. Further, when the position is detected by the phase detection,the phases of the adjacent transmitting electrodes can be changedgreatly, and it can be detected as the large phase change of thetransmitting electrodes. As a result, the position detecting system withhigh detecting accuracy and excellent reliability can be provided.

In the present invention, the axle hole is provided on the concentriccenter portion of the insulating member on which the transmittingelectrodes and the receiving electrode are formed, and the axle of therotor is inserted through the axle hole. It is preferable that the rotoris adjacent to the transmitting electrodes and the receiving electrodeon the insulating member in the non-contact manner so as to rotate.

According to this constitution, the axle of the rotor pierces the axlehole provided on the concentric center portion of the insulating member,so that the rotor can be rotated while it is adjacent to thetransmitting electrodes and the receiving electrode on the insulatingmember. For this reason, the level of the received signal induced by thereceiving electrode is made to be large, and the s/N ratio of thereceived signal can be improved.

Further, in the present invention, the relay electrode is selectivelyoverlapped with a specified transmitting electrode of the transmittingelectrodes at least not less than once while the rotor is rotating once.It is preferable example that the electrical capacity coupling betweenthe relay electrode and the specified transmitting electrode becomesmaximum.

According to this constitution, when the specified transmittingelectrode of the transmitting electrodes is selectively overlapped withthe relay electrode at least not less than once while the rotor isrotating once, the electrical capacitive coupling between the relayelectrode and the specified transmitting electrode becomes maximum. Forthis reason, only the position where the electrical capacitive couplingbecomes maximum is detected, so that the position detecting system withhigh detecting accuracy can be provided.

On the other hand, as another example in the above examples of thepresent invention, the axle hole of the insulating member has thethrough hole portion made of the electrically conductive member, and theaxle of the rotor has the relay axle portion made of the electricallyconductive member electrically connected with the relay electrodes.Further, the relay axle portion adjoins the through hole portion of theinsulating member in the non-contact manner so that they arecapacitive-coupled, and the relay signal induced by the relay axleportion can be received as the received signal by the through holeportion. According to this constitution, the relay axle portion isadjacent to the through hole portion of the axle hole on the insulatingmember in the non-contact manner so that they are capacitive-coupled. Asa result, since the relay signal induced by the relay axle portion canalso be received as the received signal by the through hole portion, thelevel of the received signal rises, and the S/N ratio is improved,thereby preventing the mis-detection of the position.

In the present invention, the ground electrode for electrical groundingis provided, and the ground electrode can be provided in the gap betweenthe transmitting electrodes and the receiving electrode formed on theinsulating member.

According to this constitution, since the electrical ground electrode isarranged in the gap between the transmitting electrodes and thereceiving electrode formed on the insulating member, the receivingelectrode is shielded by the ground electrode. For this reason, themixing of noise into the receiving electrode can be prevented, and theS/N ratio of the received signal induced by the receiving electrode canbe improved greatly.

Further, as explained in the above examples, in the fifteenth to thenineteenth examples, the integrated circuit, which includes thetransmitting circuit and the position detecting circuit for detectingthe position of the rotor, may be mounted on the insulating memberformed with the transmitting electrodes and the receiving electrode.According to this constitution, since the integrated circuit includingthe transmitting circuit and the position detecting circuit can bemounted on the one and the same insulating member, the distance betweenthe integrated circuit and the receiving electrode can be shorten,thereby preventing the mixing of noise between the integrated circuitand the receiving electrode.

In the present invention, in all the above-mentioned examples, the rotorcomposing the signal modulating means may be a part of the wheel trainmechanism. According to this constitution, it is possible to detect theposition of the wheel train mechanism, and this constitution isapplicable to the hand position detection in the watch having functions,so that this constitution is applicable to zero locating of a stopwatchand locating of a functional hand.

Further, it is desirable that the wheel train mechanism may be fordisplaying the time information. According to this constitution, theposition of the wheel train mechanism for displaying the timeinformation can be detected, and a difference in time between themechanical holding time and the electric holding time in the electricwatch is detected. As a result, the time can be corrected into correcttime, and thus this constitution is applicable to time matching of theradio wave correcting watch at the time of the reference radio wavesignal reception, and the automatic time correction when the solar cellwatch is returned from a power-saving mode into a normal mode.

Further, the operating mechanism can be a calendar mechanism. Accordingto this constitution, the position of the calendar mechanism can bedetected, so that a calendar structure, such that the calendar is fed byusing the determined results in the odd months and the even monthsaccording to the electric holding time and thus the month-end correctionis not required, can be constituted.

As is clear from the above explanations, in the position detectingsystem of the electric watch of the present invention, the transmittingelectrode and the receiving electrode are formed on the surface of theinsulating member such as one and the same printed board, and theposition of the wheel train is detected by the phase detecting meansutilizing the change in the electrical capacitive coupling between thetransmitting electrode, the receiving electrode and the relay electrodearranged on the detecting wheel. Further, the time difference betweenthe mechanical holding time and the electrical holding time in theelectric watch can be detected so as to be corrected. For this reason,the constitution of the position detecting system is simple and issuitably thinned. Further, this system is very effective for thinningand reducing the cost of the wrist watch having the automatic correctingfunction to which the position detecting function is applied.

Further, in the position detecting system, since the transmittingelectrode having high impedance can be driven, this system can be easilyapplied to power generating type electric watches which consumes lowpower and has insufficient power. Moreover, the shield structure isadded and the receiving electrode, the relay electrode and the like areimproved, so that the S/N ratio is improved, and the level of thereceived signal can be increased. For this reason, the positiondetecting system with high detecting accuracy and excellent reliabilitycan be provided.

1. An electric timepiece comprising: a transmitting circuit forgenerating a plurality of transmitted signals; a transmitting electrodefor applying output signal from said transmitting circuit; one receivingelectrode for receiving signal output from said transmitting electrode;a rotor, provided between said transmitting electrode and said receivingelectrode, for modulating said transmitted signal output from saidtransmitting electrode; a receiving circuit for inputting a modulatedsignal received by said receiving electrode; a reference signalgenerating circuit for generating a reference signal for detectingposition information of said rotor based on said transmitted signalsoutput from said transmitting circuit; and a detecting circuit forcomparing a phase of an output signal of said receiving circuit with aphase of said reference signal from said reference signal generatingcircuit so as to detect mechanical position information of said rotor,wherein said rotor is a wheel driven by a rotation movement transmittedby a wheel train from an electromechanical transducer to a rotatingmember to be measured having a hand display function, a wheel driven bya rotation movement transmitted by a wheel train from anelectromechanical transducer to a rotating member to be measured havinga date display function or a date indicator, and said detecting circuitdetects a reference position of said rotating member to be measuredbased on said mechanical position information of said rotor.
 2. Theelectric timepiece according to claim 1, wherein said detecting circuithas a phase detecting circuit and an amplitude detecting circuit, saiddetecting circuit determines a detecting range of said mechanicalposition information of said rotor from signal intensity information ofsaid received signal modulated by said rotor, and detects said positioninformation of said rotor based on phase information of said receivedsignal modulated by said rotor.
 3. The electric timepiece accordingclaim 1, wherein phases of said plurality of transmitted signals aredifferent each other and frequencies thereof are the same.
 4. Theelectric timepiece according to claim 1, wherein said transmittedsignals have sine waves or waveforms approximate to said sine wave. 5.The electric timepiece according to claim 1, wherein said detectingcircuit is a phase detecting circuit, and said detecting circuit changesan output voltage of said detecting circuit in accordance with whethersaid phase of said received signal modulated by said rotor advances ordelays with respect to that of said reference signal generated by saidreference signal generating circuit.
 6. The electric timepiece accordingto claim 1, wherein said detecting circuit comprising: delay/advancedetecting means for detecting delay or advance of said phase of saidreceived signal with respect to a phase of said reference signal as areference of phase detection and outputting a pulse signal, pulse widthof which is equal to a phase difference between said reference signaland said received signal; charge/discharge switching means for charginga capacitor with, a charging amount being proportional to said pulsewidth of said pulse signal output from said delay/advance detectingmeans, or for discharging said capacitor with, a discharging amountbeing proportional to said pulse width of said pulse signal output fromsaid delay/advance detecting means; and voltage comparing means forcomparing a terminal voltage of said capacitor with a predeterminedvoltage so as to output a compared result.
 7. The electric timepieceaccording to claim 1, wherein said rotor has such a constitution thatconductivity or permittivity of a part of a shape or a component of saidrotor is different from those in the other portion.
 8. The electrictimepiece according to claim 1, wherein said rotor is made of anelectrically conductive metal material, a part of said electricallyconductive metal material has a hole, a notch or a convexo-concaveshape.
 9. The electric timepiece according to claim 1, wherein saidrotor is made of a non-conductive member such as plastic and anelectrically conductive metal material, and a part of said metalmaterial has a hole, a notch or a convexo-concave shape.
 10. Theelectric timepiece according to claim 1, wherein said rotor is made of anon-conductive member such as plastic, and one part of saidnon-conductive member is plated with metal.
 11. The electric timepieceaccording to claim 1, wherein said rotation movement is transmitted to arotating member to be measured having a date display function or a dateindicator, and the electric timepiece has a month-end automaticcorrecting function for detecting a reference position of said rotatingmember to be measured or said date indicator based on said mechanicalposition information of said rotor and automatically eliminates amonth-end nonexistent day in the month based on electric calendarinformation held in a timepiece circuit.
 12. The electric timepieceaccording to claim 1, wherein said reference signal generating circuitshapes said plurality of transmitted signals output from saidtransmitting circuit and outputs said reference signal.
 13. The electrictimepiece according to claim 12, wherein at least said transmittingcircuit and said reference signal generating circuit are formed on oneand the same circuit chip, and an output of said transmitting circuitand an input of said reference signal generating circuit arecapacitive-coupled by a capacitor formed in said circuit chip.
 14. Theelectric timepiece according to claim 12, wherein said electrictimepiece further comprising a signal fine adjusting circuit formodulating at least said received signal or said reference signal basedon an output signal, which is output from said detecting circuit,representing a relationship between said received signal received bysaid receiving circuit and said reference signal shaped by saidreference signal generating circuit.
 15. The electric timepieceaccording to claim 14, wherein said signal fine adjusting circuit finelyadjusts said phase of said received signal or said phase of saidreference signal.
 16. The electric timepiece according to claim 14,wherein said signal fine adjusting circuit has a plurality ofcapacitors, a capacity value of which can be adjusted.
 17. The electrictimepiece according to claim 14, wherein said signal fine adjustingcircuit is provided between said transmitting circuit and saidtransmitting electrode or between said transmitting circuit and saidreference signal generating circuit.
 18. The electric timepieceaccording to claim 14, wherein said signal fine adjusting circuit iscapable of generating two or more reference signals with differentphases, and said detecting circuit selects a reference signal whosephase is separated the most from a phase showing a position of saidrotor so as to detect said position of said rotor using said selectedreference signal.
 19. The electric timepiece according to claim 1,wherein said rotor has on its rotating surface a plurality of detectingholes, each of which being provided on the respective position differentfrom each other on said rotating surface thereof, so that an angleformed between a pair of two adjacently arranged holes to each otherwith respect to a rotating axis of said rotor is different from thatformed between a separate pair of two adjacently arranged holes to eachother with respect to said rotating axis, said transmitting electrodehaving first transmitting electrodes and second transmitting electrodes,said first and said second transmitting electrodes transmit differenttransmitted signals, respectively, said first and said secondtransmitting electrodes are composed of the same number of electrodepieces as that of said detecting holes, said electrode pieces of saidfirst transmitting electrode and said electrode pieces of said secondtransmitting electrode are arranged alternatively into a ring shape, andwhen said rotor rotates once, all of said electrode pieces of either oneof said first transmitting electrodes or said second transmittingelectrodes, coincide with all of said detecting holes of said rotor,only one time.
 20. The electric timepiece according to claim 1, whereinsaid rotor has a detecting hole on its rotating surface, saidtransmitting electrode having a first transmitting electrode and asecond transmitting electrode, said first and said second transmittingelectrodes transmit different transmitted signals, respectively, saidfirst and said second transmitting electrodes are arranged into a ringshape, and when said detecting hole is on a boundary portion betweensaid transmitting electrodes, an electrode area opposed to saiddetecting hole changes according to said position of said rotor.
 21. Theelectric timepiece according to claim 1, wherein said transmittingelectrode having a first transmitting electrode and a secondtransmitting electrode, said first and said second transmittingelectrodes transmit different transmitted signals, respectively, saidfirst and said second transmitting electrodes are arranged into a ringshape, and at least one of electrode shapes on said boundary portions ofsaid two transmitting electrodes are different from said electrode shapeon another boundary portions so that a rotating direction as well assaid mechanical position information of said rotor is detected.
 22. Theelectric timepiece according to claim 1, wherein said transmittingelectrode having a first transmitting electrode and a secondtransmitting electrode, said first and said second transmittingelectrodes transmit different transmitted signals, respectively, saidfirst and said second transmitting electrodes are composed of the samenumber of electrode pieces, said electrode pieces of said firsttransmitting electrode and said electrode pieces of said secondtransmitting electrode are arranged alternatively into a ring shape, andlengths of said respective electrode pieces of one transmittingelectrode in a circumferential direction are different from each other,so that said rotating direction as well as said mechanical positioninformation of said rotor is detected.
 23. The electric timepieceaccording to claim 1, wherein said transmitting electrode having a firsttransmitting electrode, a second transmitting electrode and a thirdtransmitting electrode, said first, said second and said thirdtransmitting electrodes are arranged into a ring shape, and said first,said second and said third transmitting electrodes simultaneouslytransmit transmitting signals each having different phases,respectively.
 24. The electric timepiece according to claim 1, whereineither one of said transmitting electrode and said receiving electrodeis provided on a printed-wiring board.
 25. An electric timepiececomprising at least: a transmitting circuit for outputting twotransmitted signals with the same frequency and different phases; atransmitting electrode having a first transmitting electrode and asecond transmitting electrode arranged on an insulating member fortransmitting said two transmitted signals, respectively; a receivingelectrode formed on said insulating member; a rotor arranged so as to beopposed to said transmitting electrode and said receiving electrode; anda relay electrode formed on a rotating surface of said rotor andprovided so as to be opposed to said transmitting electrode and saidreceiving electrode, wherein said two transmitting electrodes arecomposed of a plurality of electrode pieces, respectively, saidelectrode pieces of said first transmitting electrode and said electrodepieces of said second transmitting electrode are arranged alternativelyinto a ring shape, and an area surrounded by said transmittingelectrodes is provided with said receiving electrode, wherein said relayelectrode is composed of a first area opposed to said receivingelectrode and a second area provided continuously with said first areaso as to be opposed to said transmitting electrode, wherein while saidrotor is rotating once, said entire second area of said relay electrodeis overlapped only with all said electrode pieces of either one of saidtwo transmitting electrodes at least once, and at this time, anelectrical capacity between said relay electrode and said transmittingelectrode overlapped with each other becomes maximum, further wherein,said insulating member is provided with an axle hole into which an axleof said rotor is inserted, said axle hole is formed with a through holemade of an electrically conductive member electrically connected withsaid receiving electrode, said axle of said rotor is formed with a relayaxle portion made of an electrically conductive member electricallyconnected with said relay electrode, said relay axle portion adjoinssaid through hole portion of said insulating member in a non-contactmanner so as to form electrical capacitive coupling, and said receivingelectrode receives a signal via said electrically capacitive coupling.